Project Manager doesn't need to search the main methods if a project doesn't have the Java nature

Steps to reproduce:

• start VS Code with Extension Pack for Java v0.29.2024091906 (pre-release)
• import the weblaf project

You will see the following exception:

[Error - 4:26:05 AM] Nov 16, 2024, 4:26:05?AM Problems occurred when invoking code from plug-in: "org.eclipse.jdt.ls.core".
weblaf-parent does not exist
Java Model Exception: Error in Java Model (code 969): weblaf-parent does not exist
	at org.eclipse.jdt.internal.core.JavaElement.newNotPresentException(JavaElement.java:546)
	at org.eclipse.jdt.internal.core.JavaModelManager.getPerProjectInfoCheckExistence(JavaModelManager.java:2535)
	at org.eclipse.jdt.internal.core.JavaProject.getPerProjectInfo(JavaProject.java:2329)
	at org.eclipse.jdt.internal.core.JavaProject.getResolvedClasspath(JavaProject.java:2402)
	at org.eclipse.jdt.internal.core.JavaProject.getAllPackageFragmentRoots(JavaProject.java:1774)
	at org.eclipse.jdt.internal.core.JavaProject.getAllPackageFragmentRoots(JavaProject.java:1765)
	at com.microsoft.jdtls.ext.core.ProjectCommand.getMainClasses(ProjectCommand.java:243)
	at com.microsoft.jdtls.ext.core.CommandHandler.executeCommand(CommandHandler.java:35)
	at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:230)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:220)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$4(JDTLanguageServer.java:609)
	at org.eclipse.jdt.ls.core.internal.BaseJDTLanguageServer.lambda$0(BaseJDTLanguageServer.java:87)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:690)
	at java.base/java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:527)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:507)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1458)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:2034)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:189)

Bắt đầu từ ProjectCommand.getMainClasses, điểm vào được nêu trong exception, và tái hiện vấn đề bằng cách import project weblaf được liên kết với phiên bản VS Code Java extension đã chỉ định. Hoàn tất khi việc import một project không có Java nature không còn gây ra missing-project exception trong lúc tìm các main class.