How to test Digital Signature using UI Spring Application

nites67 · May 2, 2019, 7:51am

Hi, I am using your Java UI Spring application. I need to test the Digital Signature Feature from the UI. Can you please let me know how can i do it ?

usman.aziz · May 2, 2019, 12:30pm

@nites67,

The following are the steps (along with the screenshots) to add Digital Signature to a document using our Spring application:

Load document
Select “Digital signatures” option from the L.H.S panel (see screenshot)
Upload the certificate file, fill in the form and click the “Sign” button (see screenshot)
See the confirmation message at the bottom of the document’s pages (see screenshot)
Save or Download the signed document (see screenshot)

You may also have a look at the complete video demonstration of the application here.

.

nites67 · May 2, 2019, 1:18pm

Hi, Thanks for the update. Do you have any sample certificate file to test ?

usman.aziz · May 2, 2019, 3:24pm

@nites67,

Yes, you can download the sample certificate files from our GitHub Repository.

nites67 · May 3, 2019, 9:14pm

Hi, Thanks for the update. I used acer.pfx certificate to test Digital Signature. Please find attachments. I did not get the notifications like you have showed in the screenshots which you shared after performing a digital signature. Can you please advise ?

Image 1.png (41.9 KB)
Image 2.png (80.4 KB)

usman.aziz · May 4, 2019, 3:58am

@nites67,

From the screenshots you have shared, it seems that you are using an older version of the application. Therefore, we recommend you to please download/clone the latest application that contains more user-friendly UI and extended features.

nites67 · May 7, 2019, 12:40pm

Hi, Does it required valid group docs license to test all signatures as i am not able to add any signature ? It gives me error when i try to add signatures

usman.aziz · May 7, 2019, 3:10pm

@nites67,

You may also use the application without a license, however, evaluation limitations will be applied in this case.

Could you please share with us the details of the error you are getting? You may also share the screenshots for demonstration.

nites67 · May 9, 2019, 4:56am

Hi, I have added a valid license to test but i get the below error when i click on any of the signatures. PFB

> 2019-05-09 07:53:11.254 ERROR 21012 --- [qtp641664202-19] c.g.u.s.service.SignatureServiceImpl     : Exception occurred while getting file list
> 
> com.groupdocs.ui.exception.TotalGroupDocsException: null
> 	at com.groupdocs.ui.signature.SignatureLoader.loadTextSignatures(SignatureLoader.java:97) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFilesList(SignatureServiceImpl.java:126) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFileList(SignatureServiceImpl.java:108) ~[classes/:na]
> 	at com.groupdocs.ui.signature.SignatureController.loadFileTree(SignatureController.java:86) [classes/:na]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215) [websocket-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) [jetty-security-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at java.lang.Thread.run(Unknown Source) [na:1.8.0_162]
> Caused by: java.lang.NullPointerException: null
> 	at java.util.Objects.requireNonNull(Unknown Source) ~[na:1.8.0_162]
> 	at java.util.Arrays$ArrayList.<init>(Unknown Source) ~[na:1.8.0_162]
> 	at java.util.Arrays.asList(Unknown Source) ~[na:1.8.0_162]
> 	at com.groupdocs.ui.signature.SignatureLoader.loadTextSignatures(SignatureLoader.java:94) ~[classes/:na]
> 	... 65 common frames omitted
> 
> com.groupdocs.ui.exception.TotalGroupDocsException
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFileList(SignatureServiceImpl.java:111)
> 	at com.groupdocs.ui.signature.SignatureController.loadFileTree(SignatureController.java:86)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
> 	at java.lang.reflect.Method.invoke(Unknown Source)
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877)
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655)
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531)
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352)
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281)
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762)
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680)
> 	at java.lang.Thread.run(Unknown Source)
> Caused by: com.groupdocs.ui.exception.TotalGroupDocsException
> 	at com.groupdocs.ui.signature.SignatureLoader.loadTextSignatures(SignatureLoader.java:97)
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFilesList(SignatureServiceImpl.java:126)
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFileList(SignatureServiceImpl.java:108)
> 	... 63 more
> Caused by: java.lang.NullPointerException
> 	at java.util.Objects.requireNonNull(Unknown Source)
> 	at java.util.Arrays$ArrayList.<init>(Unknown Source)
> 	at java.util.Arrays.asList(Unknown Source)
> 	at com.groupdocs.ui.signature.SignatureLoader.loadTextSignatures(SignatureLoader.java:94)
> 	... 65 more
> 2019-05-09 07:53:11.276 ERROR 21012 --- [qtp641664202-19] c.g.u.e.GroupDocsExceptionHandler        : null
> 2019-05-09 07:53:49.629  WARN 21012 --- [qtp641664202-19] org.eclipse.jetty.server.HttpChannel     : /signature/saveText
> 
> org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) ~[javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) ~[javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215) ~[websocket-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) ~[jetty-security-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at java.lang.Thread.run(Unknown Source) [na:1.8.0_162]
> Caused by: java.lang.NullPointerException: null
> 	at com.groupdocs.ui.util.Utils.createUniqueFile(Utils.java:302) ~[classes/:na]
> 	at com.groupdocs.ui.util.Utils.getFileWithUniqueName(Utils.java:297) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SaveSignatureServiceImpl.saveText(SaveSignatureServiceImpl.java:163) ~[classes/:na]
> 	at com.groupdocs.ui.signature.SignatureController.saveText(SignatureController.java:271) ~[classes/:na]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	... 49 common frames omitted
> 
> 2019-05-09 07:54:09.292  WARN 21012 --- [qtp641664202-20] org.eclipse.jetty.server.HttpChannel     : /signature/saveText
> 
> org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) ~[javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) ~[javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215) ~[websocket-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) ~[jetty-security-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at java.lang.Thread.run(Unknown Source) [na:1.8.0_162]
> Caused by: java.lang.NullPointerException: null
> 	at com.groupdocs.ui.util.Utils.createUniqueFile(Utils.java:302) ~[classes/:na]
> 	at com.groupdocs.ui.util.Utils.getFileWithUniqueName(Utils.java:297) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SaveSignatureServiceImpl.saveText(SaveSignatureServiceImpl.java:163) ~[classes/:na]
> 	at com.groupdocs.ui.signature.SignatureController.saveText(SignatureController.java:271) ~[classes/:na]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	... 49 common frames omitted
> 
> 2019-05-09 07:54:10.463  WARN 21012 --- [qtp641664202-26] org.eclipse.jetty.server.HttpChannel     : /signature/saveText
> 
> org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) ~[javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) ~[javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215) ~[websocket-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) ~[jetty-security-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) ~[jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) ~[jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at java.lang.Thread.run(Unknown Source) [na:1.8.0_162]
> Caused by: java.lang.NullPointerException: null
> 	at com.groupdocs.ui.util.Utils.createUniqueFile(Utils.java:302) ~[classes/:na]
> 	at com.groupdocs.ui.util.Utils.getFileWithUniqueName(Utils.java:297) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SaveSignatureServiceImpl.saveText(SaveSignatureServiceImpl.java:163) ~[classes/:na]
> 	at com.groupdocs.ui.signature.SignatureController.saveText(SignatureController.java:271) ~[classes/:na]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	... 49 common frames omitted
> 
> 2019-05-09 07:54:22.611 ERROR 21012 --- [qtp641664202-18] c.g.u.s.service.SignatureServiceImpl     : Exception occurred while getting file list
> 
> java.lang.NullPointerException: null
> 	at java.util.Objects.requireNonNull(Unknown Source) ~[na:1.8.0_162]
> 	at java.util.Arrays$ArrayList.<init>(Unknown Source) ~[na:1.8.0_162]
> 	at java.util.Arrays.asList(Unknown Source) ~[na:1.8.0_162]
> 	at com.groupdocs.ui.signature.SignatureLoader.loadFiles(SignatureLoader.java:72) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFilesList(SignatureServiceImpl.java:119) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFileList(SignatureServiceImpl.java:108) ~[classes/:na]
> 	at com.groupdocs.ui.signature.SignatureController.loadFileTree(SignatureController.java:86) [classes/:na]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215) [websocket-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) [jetty-security-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.ecom.groupdocs.ui.exception.TotalGroupDocsException
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFileList(SignatureServiceImpl.java:111)
> 	at com.groupdocs.ui.signature.SignatureController.loadFileTree(SignatureController.java:86)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
> 	at java.lang.reflect.Method.invoke(Unknown Source)
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877)
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655)
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531)
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352)
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281)
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762)
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680)
> 	at java.lang.Thread.run(Unknown Source)
> clipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at java.lang.Thread.run(Unknown Source) [na:1.8.0_162]
> 
> 2019-05-09 07:54:22.615 ERROR 21012 --- [qtp641664202-18] c.g.u.e.GroupDocsExceptionHandler        : null
> Caused by: java.lang.NullPointerException
> 	at java.util.Objects.requireNonNull(Unknown Source)
> 	at java.util.Arrays$ArrayList.<init>(Unknown Source)
> 	at java.util.Arrays.asList(Unknown Source)
> 	at com.groupdocs.ui.signature.SignatureLoader.loadFiles(SignatureLoader.java:72)
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFilesList(SignatureServiceImpl.java:119)
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.getFileList(SignatureServiceImpl.java:108)
> 	... 63 more
> 2019-05-09 07:54:42.586 ERROR 21012 --- [qtp641664202-18] com.groupdocs.ui.util.Utils              : Exception occurred while uploading document
> 
> java.nio.file.NoSuchFileException: F:\Work\GroupDocs.Signature-for-Java-Spring-master\DocumentSamples\SignatureData\Certificates\acer.pfx
> 	at sun.nio.fs.WindowsException.translateToIOException(Unknown Source) ~[na:1.8.0_162]
> 	at sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source) ~[na:1.8.0_162]
> 	at sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source) ~[na:1.8.0_162]
> 	at sun.nio.fs.WindowsFileSystemProvider.newByteChannel(Unknown Source) ~[na:1.8.0_162]
> 	at java.nio.file.spi.FileSystemProvider.newOutputStream(Unknown Source) ~[na:1.8.0_162]
> 	at java.nio.file.Files.newOutputStream(Unknown Source) ~[na:1.8.0_162]
> 	at java.nio.file.Files.copy(Unknown Source) ~[na:1.8.0_162]
> 	at com.groupdocs.ui.util.Utils.uploadFileInternal(Utils.java:155) ~[classes/:na]
> 	at com.groupdocs.ui.util.Utils.uploadFile(Utils.java:117) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.uploadDocument(SignatureServiceImpl.java:218) [classes/:na]
> 	at com.groupdocs.ui.signature.SignatureController.uploadDocument(SignatureController.java:161) [classes/:na]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215) [websocket-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) [jetty-security-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at java.lang.Thread.run(Unknown Source) [na:1.8.0_162]
> 
> 2019-05-09 07:54:42.587 ERROR 21012 --- [qtp641664202-18] com.groupdocs.ui.util.Utils              : Exception occurred while uploading document
> 
> com.groupdocs.ui.exception.TotalGroupDocsException: F:\Work\GroupDocs.Signature-for-Java-Spring-master\DocumentSamples\SignatureData\Certificates\acer.pfx
> 	at com.groupdocs.ui.util.Utils.uploadFile(Utils.java:120) ~[classes/:na]
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.uploadDocument(SignatureServiceImpl.java:218) [classes/:na]
> 	at com.groupdocs.ui.signature.SignatureController.uploadDocument(SignatureController.java:161) [classes/:na]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) [spring-webmvc-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [javax.servlet-api-3.1.0.jar:3.1.0]
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215) [websocket-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) [jetty-security-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) [jetty-servlet-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) [jetty-server-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) [jetty-io-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) [jetty-util-9.4.11.v20180605.jar:9.4.11.v20180605]
> 	at java.lang.Thread.run(Unknown Source) [na:1.8.0_162]
> Caused by: java.nio.file.NoSuchFileException: F:\Work\GroupDocs.Signature-for-Java-Spring-master\DocumentSamples\SignatureData\Certificates\acer.pfx
> 	at sun.nio.fs.WindowsException.translateToIOException(Unknown Source) ~[na:1.8.0_162]
> 	at sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source) ~[na:1.8.0_162]
> 	at sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source) ~[na:1.8.0_162]
> 	at sun.nio.fs.WindowsFileSystemProvider.newByteChannel(Unknown Source) ~[na:1.8.0_162]
> 	at java.nio.file.spi.FileSystemProvider.newOutputStream(Unknown Source) ~[na:1.8.0_162]
> 	at java.nio.file.Files.newOutputStream(Unknown Source) ~[na:1.8.0_162]
> 	at java.nio.file.Files.copy(Unknown Source) ~[na:1.8.0_162]
> 	at com.groupdocs.ui.util.Utils.uploadFileInternal(Utils.java:155) ~[classes/:na]
> 	at com.groupdocs.ui.util.Utils.uploadFile(Utils.java:117) ~[classes/:na]
> 	... 64 common frames omitted
> 
> com.groupdocs.ui.exception.TotalGroupDocsException: F:\Work\GroupDocs.Signature-for-Java-Spring-master\DocumentSamples\SignatureData\Certificates\acer.pfx
> 2019-05-09 07:54:42.590 ERROR 21012 --- [qtp641664202-18] c.g.u.e.GroupDocsExceptionHandler        : F:\Work\GroupDocs.Signature-for-Java-Spring-master\DocumentSamples\SignatureData\Certificates\acer.pfx
> 	at com.groupdocs.ui.util.Utils.uploadFile(Utils.java:134)
> 	at com.groupdocs.ui.signature.service.SignatureServiceImpl.uploadDocument(SignatureServiceImpl.java:218)
> 	at com.groupdocs.ui.signature.SignatureController.uploadDocument(SignatureController.java:161)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
> 	at java.lang.reflect.Method.invoke(Unknown Source)
> 	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
> 	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
> 	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
> 	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
> 	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
> 	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
> 	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
> 	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
> 	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877)
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
> 	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
> 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
> 	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655)
> 	at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:215)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
> 	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
> 	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
> 	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
> 	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
> 	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
> 	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
> 	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
> 	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
> 	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219)
> 	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
> 	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
> 	at org.eclipse.jetty.server.Server.handle(Server.java:531)
> 	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352)
> 	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
> 	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281)
> 	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
> 	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
> 	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
> 	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762)
> 	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680)
> 	at java.lang.Thread.run(Unknown Source)
> Caused by: com.groupdocs.ui.exception.TotalGroupDocsException: F:\Work\GroupDocs.Signature-for-Java-Spring-master\DocumentSamples\SignatureData\Certificates\acer.pfx
> 	at com.groupdocs.ui.util.Utils.uploadFile(Utils.java:120)
> 	... 64 more
> Caused by: java.nio.file.NoSuchFileException: F:\Work\GroupDocs.Signature-for-Java-Spring-master\DocumentSamples\SignatureData\Certificates\acer.pfx
> 	at sun.nio.fs.WindowsException.translateToIOException(Unknown Source)
> 	at sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source)
> 	at sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source)
> 	at sun.nio.fs.WindowsFileSystemProvider.newByteChannel(Unknown Source)
> 	at java.nio.file.spi.FileSystemProvider.newOutputStream(Unknown Source)
> 	at java.nio.file.Files.newOutputStream(Unknown Source)
> 	at java.nio.file.Files.copy(Unknown Source)
> 	at com.groupdocs.ui.util.Utils.uploadFileInternal(Utils.java:155)
> 	at com.groupdocs.ui.util.Utils.uploadFile(Utils.java:117)
> 	... 64 more

usman.aziz · May 9, 2019, 6:28am

@nites67,

We are able to reproduce the same behavior at our end. This issue is already logged in our GitHub issues as Selecting any signature type returns null · Issue #29 · groupdocs-signature/GroupDocs.Signature-for-Java-Spring · GitHub. We shall keep you updated as soon as we have any news about the fix.

usman.aziz · May 16, 2019, 8:43am

@nites67,

Your reported issue, logged as Selecting any signature type returns null · Issue #29 · groupdocs-signature/GroupDocs.Signature-for-Java-Spring · GitHub, has been fixed. Please download/clone the latest application from the GitHub repository.

nites67 · May 18, 2019, 9:06am

Thank you very much for the update. I will check. Btw i have one question. In the Spring UI application, Is it possible to include both annotation and signature features in one page when we open the document ?
Currently, I see that they are two different projects.

usman.aziz · May 18, 2019, 6:01pm

@nites67,

You are welcome.

Yes, you can include the features of both APIs, GroupDocs.Signature and GroupDocs.Annotation, into a single front end application. Since the Spring UI applications are open source, you can easily add (or update) the features that you require. Though we don’t have a single application having features of both APIs, you can combine the features provided by both front ends into a single application on your own as per your use case.