added check for availability of the tools.jar types

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/BootJavaLanguageServerComponents.java

@@ -256,7 +256,6 @@ public class BootJavaLanguageServerComponents implements LanguageServerComponent
 	}
 
 	private void shutdown() {
-//		this.liveHoverWatchdog.shutdown();
 		this.liveProcessTracker.stop();
 		this.liveChangeDetectionWatchdog.shutdown();
 		this.cuCache.dispose();

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/livehover/v2/SpringProcessConnectorLocal.java

@@ -87,6 +87,20 @@ public class SpringProcessConnectorLocal {
 		});
 	}
 	
+	/**
+	 * checks whether this class can operate normally or not - it is recommended to check this before calling out to this class
+	 * (if the attach to VirtualMachine library is not around, this class cannot really do anything and will throw exceptions)
+	 */
+	public static boolean isAvailable() {
+		try {
+			Class<?> vmClass = VirtualMachine.class;
+			return vmClass != null;
+		}
+		catch (NoClassDefFoundError e) {
+			return false;
+		}
+	}
+
 	public void searchForNewProcesses() {
 		List<VirtualMachineDescriptor> currentVms = VirtualMachine.list();
 		Set<String> currentVMKeys = new HashSet<>();
@@ -211,5 +225,5 @@ public class SpringProcessConnectorLocal {
 		int firstSpace = rawName.indexOf(' ');
 		return firstSpace < 0 ? rawName : rawName.substring(0, firstSpace);
 	}
-
+	
 }

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/livehover/v2/SpringProcessTracker.java

@@ -27,6 +27,7 @@ public class SpringProcessTracker {
 
 	private final long POLLING_INTERVAL_MILLISECONDS;
 	private final SpringProcessConnectorLocal localProcessConnector;
+	private final boolean isConnectorAvailable;
 
 	private boolean automaticTrackingEnabled;
 	private ScheduledThreadPoolExecutor timer;
@@ -35,16 +36,28 @@ public class SpringProcessTracker {
 		this.localProcessConnector = localProcessConnector;
 		this.POLLING_INTERVAL_MILLISECONDS = pollingInterval == null ? DEFAULT_INTERVAL.toMillis() : pollingInterval.toMillis();
 		this.automaticTrackingEnabled = true;
+		
+		this.isConnectorAvailable = SpringProcessConnectorLocal.isAvailable();
 	}
 
 	public synchronized void setTrackingEnabled(boolean trackingEnabled) {
 		if (automaticTrackingEnabled != trackingEnabled) {
 			automaticTrackingEnabled = trackingEnabled;
-			refresh();
+
+			if (automaticTrackingEnabled) {
+				start();
+			} else {
+				stop();
+			}
 		}
 	}
 
 	public synchronized void start() {
+		if (!isConnectorAvailable) {
+			log.error("virtual machine connector library not available, no automatic local process tracking possible");
+			return;
+		}
+		
 		if (automaticTrackingEnabled && timer == null) {
 			log.info("Starting SpringProcessTracker");
 			this.timer = new ScheduledThreadPoolExecutor(1);
@@ -70,12 +83,4 @@ public class SpringProcessTracker {
 		}
 	}
 
-	private void refresh() {
-		if (automaticTrackingEnabled) {
-			start();
-		} else {
-			stop();
-		}
-	}
-
 }