Can't resolve imports on an Eclipse project

Just tried the extension on an existing eclipse project, no imports could be resolved, not even the java.lang ones:

On output console:

[Warn - 3:12:21 PM] Aug 23, 2017 3:12:15 PM While loading class "org.eclipse.m2e.core.MavenPlugin", thread "Thread[Worker-2,5,main]" timed out waiting (5154ms) for thread "Thread[pool-1-thread-1,5,main]" to finish starting bundle "org.eclipse.m2e.core_1.8.1.20170728-1531 [52]". To avoid deadlock, thread "Thread[Worker-2,5,main]" is proceeding but "org.eclipse.m2e.core.MavenPlugin" may not be fully initialized.
Unable to acquire the state change lock for the module: osgi.identity; type="osgi.bundle"; version:Version="1.8.1.20170728-1531"; osgi.identity="org.eclipse.m2e.core"; singleton:="true" [id=52] STARTED [STARTED]
org.osgi.framework.BundleException: Unable to acquire the state change lock for the module: osgi.identity; type="osgi.bundle"; version:Version="1.8.1.20170728-1531"; osgi.identity="org.eclipse.m2e.core"; singleton:="true" [id=52] STARTED [STARTED]
at org.eclipse.osgi.container.Module.lockStateChange(Module.java:337)
at org.eclipse.osgi.container.Module.start(Module.java:401)
at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:468)
at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:103)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:529)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:328)
at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:368)
at org.eclipse.osgi.internal.loader.sources.SingleSourcePackage.loadClass(SingleSourcePackage.java:36)
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:442)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:395)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:387)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:150)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.eclipse.jdt.ls.core.internal.managers.MavenProjectImporter.(MavenProjectImporter.java:53)
at org.eclipse.jdt.ls.core.internal.managers.ProjectsManager.importers(ProjectsManager.java:176)
at org.eclipse.jdt.ls.core.internal.managers.ProjectsManager.getImporter(ProjectsManager.java:160)
at org.eclipse.jdt.ls.core.internal.managers.ProjectsManager.initializeProjects(ProjectsManager.java:73)
at org.eclipse.jdt.ls.core.internal.handlers.InitHandler$1.run(InitHandler.java:117)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:56)
Caused by: java.util.concurrent.TimeoutException: Timeout after waiting 5 seconds to acquire the lock.
at org.eclipse.osgi.container.Module.lockStateChange(Module.java:334)
... 18 more

On the VSCode developer tools:

/C:/Program Files (x86)/Microsoft VS Code/resources/app/out/vs/workbench/workbench.main.js:29 Invalid arguments: Error: Invalid arguments
at new e (c:\Program Files (x86)\Microsoft VS Code\resources\app\out\vs\workbench\node\extensionHostProcess.js:23:230953)
at asRange (C:\Users\gabriel.barroso.vscode\extensions\redhat.java-0.8.0\node_modules\vscode-languageclient\lib\protocolConverter.js:41:16)
at asLocation (C:\Users\gabriel.barroso.vscode\extensions\redhat.java-0.8.0\node_modules\vscode-languageclient\lib\protocolConverter.js:205:59)
at item.map (C:\Users\gabriel.barroso.vscode\extensions\redhat.java-0.8.0\node_modules\vscode-languageclient\lib\protocolConverter.js:195:43)
at Array.map (native)
at asDefinitionResult (C:\Users\gabriel.barroso.vscode\extensions\redhat.java-0.8.0\node_modules\vscode-languageclient\lib\protocolConverter.js:195:25)

Environment

• Windows 10:
• JDK version 8:
• Visual Studio Code version 1.15:
• Java extension version: 0.8.0

まず、既存の Eclipse プロジェクトで未解決の import の動作を再現し、stack trace にある MavenProjectImporter と ProjectsManager のエントリーポイントを調査します。language server の出力を vscode-languageclient protocolConverter.js のエラーと比較します。標準 import とプロジェクト import が、報告されている初期化または定義結果の失敗なしに解決されれば完了です。