Avoid unnecessary project updates when the default vm changes

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JVMConfigurator.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2019-2020 Red Hat Inc. and others.
+ * Copyright (c) 2019-2022 Red Hat Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
@@ -302,8 +302,7 @@ public void defaultVMInstallChanged(IVMInstall previous, IVMInstall current) {
 				configureJVMSettings(javaProject, current);
 			}
 			ProjectsManager projectsManager = JavaLanguageServerPlugin.getProjectsManager();
-			if (projectsManager != null) {
-				//TODO Only trigger update if the project uses the default JVM
+			if (projectsManager != null && projectsManager.useDefaultVM(project, current)) {
 				JavaLanguageServerPlugin.logInfo("defaultVMInstallChanged -> force update of " + project.getName());
 				projectsManager.updateProject(project, true);
 			}

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/managers/GradleBuildSupport.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016-2020 Red Hat Inc. and others.
+ * Copyright (c) 2016-2022 Red Hat Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
@@ -42,6 +42,7 @@
 import org.eclipse.jdt.core.IJavaProject;
 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.JavaModelException;
+import org.eclipse.jdt.launching.IVMInstall;
 import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
 import org.eclipse.jdt.ls.core.internal.ProjectUtils;
 import org.eclipse.jdt.ls.core.internal.ResourceUtils;
@@ -163,6 +164,11 @@ public boolean fileChanged(IResource resource, CHANGE_TYPE changeType, IProgress
 		return IBuildSupport.super.fileChanged(resource, changeType, monitor) || isBuildFile(resource);
 	}
 
+	@Override
+	public boolean useDefaultVM(IProject project, IVMInstall defaultVM) {
+		return GradleProjectImporter.useDefaultVM();
+	}
+
 	/**
 	 * save gradle project preferences
 	 *

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/managers/GradleProjectImporter.java

@@ -467,6 +467,17 @@ public static BuildConfiguration getBuildConfiguration(Path rootFolder) {
 		return build;
 	}
 
+	static boolean useDefaultVM() {
+		File javaHome = getGradleJavaHomeFile();
+		if (javaHome == null) {
+			IVMInstall javaDefaultRuntime = JavaRuntime.getDefaultVMInstall();
+			return javaDefaultRuntime != null
+				&& javaDefaultRuntime.getVMRunner(ILaunchManager.RUN_MODE) != null;
+		}
+
+		return false;
+	}
+
 	private static File getJavaHome(Preferences preferences) {
 		File javaHome = getGradleJavaHomeFile();
 		if (javaHome == null) {

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/managers/IBuildSupport.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016-2020 Red Hat Inc. and others.
+ * Copyright (c) 2016-2022 Red Hat Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
@@ -25,6 +25,7 @@
 import org.eclipse.debug.core.ILaunchConfiguration;
 import org.eclipse.jdt.core.IClassFile;
 import org.eclipse.jdt.core.IJavaProject;
+import org.eclipse.jdt.launching.IVMInstall;
 import org.eclipse.jdt.ls.core.internal.ProjectUtils;
 import org.eclipse.jdt.ls.core.internal.managers.ProjectsManager.CHANGE_TYPE;
 import org.eclipse.jdt.ls.core.internal.preferences.PreferenceManager;
@@ -81,6 +82,13 @@ default boolean fileChanged(IResource resource, CHANGE_TYPE changeType, IProgres
 		return false;
 	}
 
+	/**
+	 * Check if the build support for the specified project depends on the default VM.
+	 */
+	default boolean useDefaultVM(IProject project, IVMInstall defaultVM) {
+		return false;
+	}
+
 	default void refresh(IResource resource, CHANGE_TYPE changeType, IProgressMonitor monitor) throws CoreException {
 		if (resource == null) {
 			return;

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/managers/ProjectsManager.java

@@ -443,6 +443,22 @@ public Optional<IBuildSupport> getBuildSupport(IProject project) {
 		return buildSupports().filter(bs -> bs.applies(project)).findFirst();
 	}
 
+	/**
+	 * Check if the build support for the specified project depends on the default VM.
+	 */
+	public boolean useDefaultVM(IProject project, IVMInstall defaultVM) {
+		if (project == null) {
+			return false;
+		}
+
+		IBuildSupport buildSupport = getBuildSupport(project).orElse(null);
+		if (buildSupport != null) {
+			return buildSupport.useDefaultVM(project, defaultVM);
+		}
+
+		return false;
+	}
+
 	private Stream<IBuildSupport> buildSupports() {
 		return Stream.of(new EclipseBuildSupport());
 	}