[Jdt.Ls]Show implementations doesn't work correct in specific case

[vparfonov]

Problem reproduced with test ImplementationBaseOperationsTest but will be more easy reproduce it manually.

Step to reproduce:

1. Clone project https://github.com/vparfonov/test-project.git
2. Set project type as Maven
3. Open class file /test-project/src/main/java/com/codenvy/qa/Empl.java
4. Set cursor position to the 16:44
5. Run action Assistance-> Implementations

Expected result:

Popup with implementations for Serializable

Actual:

Any reaction on UI, but got exception in console of dev-machine

dev-machine log

Started language servers initialization, file path 'file:///projects/init.java'
2018-08-20 14:53:16,404[rverInitializer]  [INFO ] [anguageServerConfigInitializer 63]   - Language server config processing: started
2018-08-20 14:53:16,405[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 134]  - Finished language servers initialization, file path 'file:///projects/init.java'
2018-08-20 14:53:16,891[ool-10-thread-1]  [ERROR] [o.e.c.a.l.CheLanguageClient 75]      - Aug 20, 2018 2:53:16 PM An internal error occurred during: "Validate documents".
java.lang.NullPointerException
null
	at org.eclipse.jdt.ls.core.internal.ResourceUtils.fixURI(ResourceUtils.java:127)
	at org.eclipse.jdt.ls.core.internal.handlers.DocumentLifeCycleHandler.access$0(DocumentLifeCycleHandler.java:121)
	at org.eclipse.jdt.ls.core.internal.handlers.DocumentLifeCycleHandler.performValidation(DocumentLifeCycleHandler.java:147)
	at org.eclipse.jdt.ls.core.internal.JDTUtils.toURI(JDTUtils.java:512)
	at org.eclipse.jdt.ls.core.internal.handlers.DiagnosticsHandler.<init>(DiagnosticsHandler.java:47)
	at org.eclipse.jdt.ls.core.internal.JDTUtils.getFileURI(JDTUtils.java:521)
	at org.eclipse.core.internal.resources.InternalWorkspaceJob.run(InternalWorkspaceJob.java:39)
 
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
	at org.eclipse.jdt.ls.core.internal.handlers.DocumentLifeCycleHandler$1.runInWorkspace(DocumentLifeCycleHandler.java:89)
2018-08-20 14:53:24,662[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 117]  - Started language servers initialization, file path 'file:///projects/init.java'
2018-08-20 14:53:24,663[rverInitializer]  [INFO ] [anguageServerConfigInitializer 63]   - Language server config processing: started
2018-08-20 14:53:24,665[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 134]  - Finished language servers initialization, file path 'file:///projects/init.java'
java.lang.NullPointerException
	at org.eclipse.che.jdt.ls.extension.core.internal.navigation.FindImplementersHandler.findSubTypes(FindImplementersHandler.java:98)
null
	at org.eclipse.che.jdt.ls.extension.core.internal.navigation.FindImplementersHandler.convertToSymbolInformation(FindImplementersHandler.java:135)
	at org.eclipse.che.jdt.ls.extension.core.internal.navigation.FindImplementersHandler.getImplementers(FindImplementersHandler.java:78)
	at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:151)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:411)
2018-08-20 14:53:28,115[ool-10-thread-1]  [ERROR] [o.e.c.a.l.CheLanguageClient 75]      - Aug 20, 2018 2:53:28 PM Problems occurred when invoking code from plug-in: "org.eclipse.jdt.ls.core".
	at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:141)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.che.jdt.ls.extension.core.internal.CheDelegateCommandHandler.executeCommand(CheDelegateCommandHandler.java:113)
	at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$23(JDTLanguageServer.java:732)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
null
	at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
2018-08-20 14:53:28,116[ool-10-thread-1]  [ERROR] [o.e.c.a.l.CheLanguageClient 75]      - Aug 20, 2018 2:53:28 PM Error in calling delegate command handler
	at org.eclipse.che.jdt.ls.extension.core.internal.navigation.FindImplementersHandler.convertToSymbolInformation(FindImplementersHandler.java:135)
	at org.eclipse.che.jdt.ls.extension.core.internal.navigation.FindImplementersHandler.findSubTypes(FindImplementersHandler.java:98)
 
	at org.eclipse.che.jdt.ls.extension.core.internal.CheDelegateCommandHandler.executeCommand(CheDelegateCommandHandler.java:113)
	at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:151)
	at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:141)
java.lang.NullPointerException
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$23(JDTLanguageServer.java:732)
	at org.eclipse.che.jdt.ls.extension.core.internal.navigation.FindImplementersHandler.getImplementers(FindImplementersHandler.java:78)
	at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
	at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:411)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
 
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
2018-08-20 15:00:25,927[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 117]  - Started language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:00:25,930[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 134]  - Finished language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:00:25,928[rverInitializer]  [INFO ] [anguageServerConfigInitializer 63]   - Language server config processing: started
2018-08-20 15:00:25,944[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 117]  - Started language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:00:25,944[rverInitializer]  [INFO ] [anguageServerConfigInitializer 63]   - Language server config processing: started
2018-08-20 15:00:25,945[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 134]  - Finished language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:06:18,602[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 117]  - Started language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:06:18,602[rverInitializer]  [INFO ] [anguageServerConfigInitializer 63]   - Language server config processing: started
2018-08-20 15:06:18,603[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 134]  - Finished language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:06:18,617[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 117]  - Started language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:06:18,618[rverInitializer]  [INFO ] [anguageServerConfigInitializer 63]   - Language server config processing: started
2018-08-20 15:06:18,618[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 134]  - Finished language servers initialization, file path 'file:///projects/init.java'
2018-08-20 15:11:58,964[rverInitializer]  [INFO ] [anguageServerConfigInitializer 63]   - Language server config processing: started
2018-08-20 15:11:58,963[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 117]  - Started language servers initialization, file path 'jdt:/contents/rt.jar/java.io/Serializable.class?=PR/%5C/usr%5C/lib%5C/jvm%5C/java-8-openjdk-amd64%5C/jre%5C/lib%5C/rt.jar%3Cjava.io(Serializable.class'
2018-08-20 15:11:58,969[rverInitializer]  [INFO ] [.a.l.LanguageServerInitializer 134]  - Finished language servers initialization, file path 'jdt:/contents/rt.jar/java.io/Serializable.class?=PR/%5C/usr%5C/lib%5C/jvm%5C/java-8-openjdk-amd64%5C/jre%5C/lib%5C/rt.jar%3Cjava.io(Serializable.class'

In websocket channel:

Request:
{"jsonrpc":"2.0","method":"java/implementers","id":"27","params":{"position":{"line":15,"character":43},"textDocument":{"uri":"/test-project/src/main/java/com/codenvy/qa/Empl.java"}}}
Response:
{"jsonrpc":"2.0","id":"27","error":{"code":-27000,"message":"org.eclipse.lsp4j.jsonrpc.ResponseErrorException"}}

Note:

Same situation in master branch works correct