Java Model Exception: Java Model Status [src/main/java/suddenly.in.dot.notation [in some-maven-submodule] is not on its project's build path]

I have a maven project, with 5 submodules, nothing too special, Spring Boot 2, Lombok, AWS SDK. Project builds fine, ie, I can mvn test/compile/package/install to hearts' delight.

When I open this project in VS Code, I get the following errors (many of them, see also attached log):

!ENTRY org.eclipse.jdt.ls.core 4 0 2018-07-11 18:14:02.128
!MESSAGE Failed to publish diagnostics.
!STACK 1
Java Model Exception: Java Model Status [src/main/java/this.in.dot.notation.why [in aesop-dfp] is not on its project's build path]
	at org.eclipse.jdt.internal.core.JavaElement.newJavaModelException(JavaElement.java:580)
	at org.eclipse.jdt.internal.core.Openable.generateInfos(Openable.java:253)
	at org.eclipse.jdt.internal.core.Openable.openAncestors(Openable.java:527)
	at org.eclipse.jdt.internal.core.Openable.generateInfos(Openable.java:247)
	at org.eclipse.jdt.internal.core.Openable.openAncestors(Openable.java:527)
	at org.eclipse.jdt.internal.core.CompilationUnit.openAncestors(CompilationUnit.java:1240)
	at org.eclipse.jdt.internal.core.Openable.generateInfos(Openable.java:247)
	at org.eclipse.jdt.internal.core.JavaElement.openWhenClosed(JavaElement.java:593)
	at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:323)
	at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:309)
	at org.eclipse.jdt.internal.core.Openable.getBuffer(Openable.java:295)
	at org.eclipse.jdt.ls.core.internal.handlers.BuildWorkspaceHandler.publishDiagnostics(BuildWorkspaceHandler.java:112)
	at org.eclipse.jdt.ls.core.internal.handlers.BuildWorkspaceHandler.buildWorkspace(BuildWorkspaceHandler.java:65)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$21(JDTLanguageServer.java:672)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$22(JDTLanguageServer.java:716)
	at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
	at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
	at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
!SUBENTRY 1 org.eclipse.jdt.core 4 1006 2018-07-11 18:14:02.132
!MESSAGE src/main/java/this.in.dot.notation.why [in aesop-dfp] is not on its project's build path

Note: I changed the package name.

Environment

• Operating System: Windows 10 x64
• JDK version: OpenJDK 8 r163 x64
• Visual Studio Code version: 1.25.0
• Java extension version: 0.28.0

Steps To Reproduce

1. Open Maven project in VS code
2. Open log file (see attached)

jdt-ls.log

Current Result

Code completion doesn't work.

Expected Result

Code completion works.

Bắt đầu với jdt-ls.log được đính kèm và lần theo stack trace qua BuildWorkspaceHandler.publishDiagnostics/buildWorkspace và JDTLanguageServer. Tái hiện thiết lập dự án Maven gồm năm submodule được mô tả trong issue, sau đó xác minh rằng các chẩn đoán của workspace không còn báo cáo các mã nguồn Java nằm ngoài build path và tính năng hoàn thành mã hoạt động.