Remove listeners in MinimalState if bundle is stopped

This change adapts the listeners that have been added with
24e9bb5 so that they are removed again,
once the bundle is shut down and thus makes the classloader eligible for
garbage collection.

Author: ptziegler

ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/MinimalState.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2005, 2024 IBM Corporation and others.
+ * Copyright (c) 2005, 2025 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -37,6 +37,7 @@
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
 import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.jdt.core.IJavaProject;
 import org.eclipse.jdt.core.JavaCore;
@@ -65,6 +66,38 @@
 
 public class MinimalState {
 
+	private static final IPreferenceChangeListener PREF_CHANGE_LISTENER = e -> {
+		if (e.getKey().equals("org.eclipse.jdt.launching.PREF_DEFAULT_ENVIRONMENTS_XML")) { //$NON-NLS-1$
+			Object oldValue = e.getOldValue() == null ? "" : e.getOldValue(); //$NON-NLS-1$
+			Object newValue = e.getNewValue() == null ? "" : e.getNewValue(); //$NON-NLS-1$
+			if (!oldValue.equals(newValue)) {
+				triggerSystemPackagesReload();
+			}
+		}
+	};
+
+	private static final IVMInstallChangedListener VM_CHANGED_LISTENER = new IVMInstallChangedListener() {
+		@Override
+		public void vmRemoved(IVMInstall vm) {
+			triggerSystemPackagesReload();
+		}
+
+		@Override
+		public void vmChanged(PropertyChangeEvent event) {
+			triggerSystemPackagesReload();
+		}
+
+		@Override
+		public void vmAdded(IVMInstall vm) {
+			triggerSystemPackagesReload();
+		}
+
+		@Override
+		public void defaultVMInstallChanged(IVMInstall previous, IVMInstall current) {
+			triggerSystemPackagesReload();
+		}
+	};
+
 	protected State fState;
 
 	protected long fId;
@@ -268,39 +301,20 @@ protected boolean initializePlatformProperties() {
 	static {
 		// Listen to changes in the available VMInstalls and
 		// ExecutionEnvironment defaults
-		@SuppressWarnings("restriction")
-		String nodeQualifier = org.eclipse.jdt.internal.launching.LaunchingPlugin.ID_PLUGIN;
-		IEclipsePreferences launchingNode = InstanceScope.INSTANCE.getNode(nodeQualifier);
-		launchingNode.addPreferenceChangeListener(e -> {
-			if (e.getKey().equals("org.eclipse.jdt.launching.PREF_DEFAULT_ENVIRONMENTS_XML")) { //$NON-NLS-1$
-				Object oldValue = e.getOldValue() == null ? "" : e.getOldValue(); //$NON-NLS-1$
-				Object newValue = e.getNewValue() == null ? "" : e.getNewValue(); //$NON-NLS-1$
-				if (!oldValue.equals(newValue)) {
-					triggerSystemPackagesReload();
-				}
-			}
-		});
-		JavaRuntime.addVMInstallChangedListener(new IVMInstallChangedListener() {
-			@Override
-			public void vmRemoved(IVMInstall vm) {
-				triggerSystemPackagesReload();
-			}
-
-			@Override
-			public void vmChanged(PropertyChangeEvent event) {
-				triggerSystemPackagesReload();
-			}
+		IEclipsePreferences launchingNode = getJdtLaunchingPreferences();
+		launchingNode.addPreferenceChangeListener(PREF_CHANGE_LISTENER);
+		JavaRuntime.addVMInstallChangedListener(VM_CHANGED_LISTENER);
+	}
 
-			@Override
-			public void vmAdded(IVMInstall vm) {
-				triggerSystemPackagesReload();
-			}
+	static void shutdown() {
+		IEclipsePreferences launchingNode = getJdtLaunchingPreferences();
+		launchingNode.removePreferenceChangeListener(PREF_CHANGE_LISTENER);
+		JavaRuntime.removeVMInstallChangedListener(VM_CHANGED_LISTENER);
+	}
 
-			@Override
-			public void defaultVMInstallChanged(IVMInstall previous, IVMInstall current) {
-				triggerSystemPackagesReload();
-			}
-		});
+	@SuppressWarnings("restriction")
+	private static IEclipsePreferences getJdtLaunchingPreferences() {
+		return InstanceScope.INSTANCE.getNode(org.eclipse.jdt.internal.launching.LaunchingPlugin.ID_PLUGIN);
 	}
 
 	public static void triggerSystemPackagesReload() {

ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/PDECore.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2018 IBM Corporation and others.
+ * Copyright (c) 2000, 2025 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -424,6 +424,8 @@ public void stop(BundleContext context) throws CoreException {
 		IWorkspace workspace = ResourcesPlugin.getWorkspace();
 		workspace.removeSaveParticipant(PLUGIN_ID);
 		workspace.removeResourceChangeListener(bndResourceChangeListener);
+
+		MinimalState.shutdown();
 	}
 
 	/**