Ignore the NPE which happens when dropping a rocket component as the

last component in the previous child element.  I can't seem to find a
better solution than to just eat the npe.

swing/src/net/sf/openrocket/gui/main/SwingExceptionHandler.java

@@ -13,49 +13,49 @@ import org.slf4j.LoggerFactory;
 
 
 public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, ExceptionHandler {
-	
+
 	private static final Logger log = LoggerFactory.getLogger(SwingExceptionHandler.class);
-	
+
 	private static final int MEMORY_RESERVE = 512 * 1024;
-	
+
 	/**
 	 * A memory reserve of 0.5 MB of memory, that can be freed when showing the dialog.
 	 * <p>
 	 * This field is package-private so that the JRE cannot optimize its use away.
 	 */
 	volatile byte[] memoryReserve = null;
-	
+
 	private volatile boolean handling = false;
-	
+
-	
+
-	
+
-	
+
 	@Override
 	public void uncaughtException(final Thread thread, final Throwable throwable) {
-		
+
 		// Free memory reserve if out of memory
 		if (isOutOfMemoryError(throwable)) {
 			memoryReserve = null;
 			handling = false;
 			log.error("Out of memory error detected", throwable);
 		}
-		
+
 		if (isNonFatalJREBug(throwable)) {
 			log.warn("Ignoring non-fatal JRE bug", throwable);
 			return;
 		}
-		
+
 		log.error("Handling uncaught exception on thread=" + thread, throwable);
 		throwable.printStackTrace();
-		
+
 		if (handling) {
 			log.warn("Exception is currently being handled, ignoring");
 			return;
 		}
-		
+
 		try {
 			handling = true;
-			
+
 			// Show on the EDT
 			if (SwingUtilities.isEventDispatchThread()) {
 				log.info("Exception handler running on EDT, showing dialog");
@@ -69,9 +69,9 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 					}
 				});
 			}
-			
+
 		} catch (Throwable ex) {
-			
+
 			// Make sure the handler does not throw any exceptions
 			try {
 				log.error("Caught exception while handling exception", ex);
@@ -79,15 +79,15 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 				ex.printStackTrace();
 			} catch (Exception ignore) {
 			}
-			
+
 		} finally {
 			// Mark handling as completed
 			handling = false;
 		}
-		
+
 	}
-	
+
-	
+
 	/**
 	 * Handle an error condition programmatically without throwing an exception.
 	 * This can be used in cases where recovery of the error is desirable.
@@ -102,8 +102,8 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 		log.error(message, new Throwable());
 		handleErrorCondition(new InternalException(message));
 	}
-	
+
-	
+
 	/**
 	 * Handle an error condition programmatically without throwing an exception.
 	 * This can be used in cases where recovery of the error is desirable.
@@ -119,8 +119,8 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 		log.error(message, exception);
 		handleErrorCondition(new InternalException(message, exception));
 	}
-	
+
-	
+
 	/**
 	 * Handle an error condition programmatically without throwing an exception.
 	 * This can be used in cases where recovery of the error is desirable.
@@ -137,7 +137,7 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 				log.error("Error occurred", exception);
 			}
 			final Thread thread = Thread.currentThread();
-			
+
 			if (SwingUtilities.isEventDispatchThread()) {
 				log.info("Running in EDT, showing dialog");
 				this.showDialog(thread, exception);
@@ -155,8 +155,8 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 			log.error("Exception occurred in error handler", e);
 		}
 	}
-	
+
-	
+
 	/**
 	 * The actual handling routine.
 	 * 
@@ -164,82 +164,82 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 	 * @param e		the exception.
 	 */
 	private void showDialog(Thread t, Throwable e) {
-		
+
 		// Out of memory
 		if (isOutOfMemoryError(e)) {
 			log.info("Showing out-of-memory dialog");
 			JOptionPane.showMessageDialog(null,
 					new Object[] {
-							"OpenRocket is out of available memory!",
+					"OpenRocket is out of available memory!",
-							"You should immediately close unnecessary design windows,",
+					"You should immediately close unnecessary design windows,",
-							"save any unsaved designs and restart OpenRocket!"
+					"save any unsaved designs and restart OpenRocket!"
-					}, "Out of memory", JOptionPane.ERROR_MESSAGE);
+			}, "Out of memory", JOptionPane.ERROR_MESSAGE);
 			return;
 		}
-		
+
 		// Create the message
 		String msg = e.getClass().getSimpleName() + ": " + e.getMessage();
 		if (msg.length() > 90) {
 			msg = msg.substring(0, 80) + "...";
 		}
-		
+
 		// Unknown Error
 		if (!(e instanceof Exception) && !(e instanceof LinkageError)) {
 			log.info("Showing Error dialog");
 			JOptionPane.showMessageDialog(null,
 					new Object[] {
-							"An unknown Java error occurred:",
+					"An unknown Java error occurred:",
-							msg,
+					msg,
-							"<html>You should immediately close unnecessary design windows,<br>" +
+					"<html>You should immediately close unnecessary design windows,<br>" +
-									"save any unsaved designs and restart OpenRocket!"
+							"save any unsaved designs and restart OpenRocket!"
-					}, "Unknown Java error", JOptionPane.ERROR_MESSAGE);
+			}, "Unknown Java error", JOptionPane.ERROR_MESSAGE);
 			return;
 		}
-		
+
-		
+
 		// Normal exception, show question dialog		
 		log.info("Showing Exception dialog");
 		int selection = JOptionPane.showOptionDialog(null, new Object[] {
 				"OpenRocket encountered an uncaught exception.  This typically signifies " +
 						"a bug in the software.",
-				"<html><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;" + msg + "</em>",
+						"<html><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;" + msg + "</em>",
-				" ",
+						" ",
-				"Please take a moment to report this bug to the developers.",
+						"Please take a moment to report this bug to the developers.",
-				"This can be done automatically if you have an Internet connection."
+						"This can be done automatically if you have an Internet connection."
 		}, "Uncaught exception", JOptionPane.DEFAULT_OPTION,
-				JOptionPane.ERROR_MESSAGE, null,
+		JOptionPane.ERROR_MESSAGE, null,
-				new Object[] { "View bug report", "Close" }, "View bug report");
+		new Object[] { "View bug report", "Close" }, "View bug report");
-		
+
 		if (selection != 0) {
 			// User cancelled
 			log.info(Markers.USER_MARKER, "User chose not to fill bug report");
 			return;
 		}
-		
+
 		// Show bug report dialog
 		log.info(Markers.USER_MARKER, "User requested sending bug report");
 		BugReportDialog.showExceptionDialog(null, t, e);
 	}
-	
+
-	
+
-	
+
 	/**
 	 * Registers the uncaught exception handler.  This should be used to ensure that
 	 * all necessary registrations are performed.
 	 */
 	public void registerExceptionHandler() {
-		
+
 		Thread.setDefaultUncaughtExceptionHandler(this);
-		
+
 		// Handler for modal dialogs of Sun's Java implementation
 		// See bug ID 4499199.
 		System.setProperty("sun.awt.exception.handler", AwtHandler.class.getName());
-		
+
 		reserveMemory();
-		
+
 	}
-	
+
-	
+
 	/**
 	 * Reserve the buffer memory that is freed in case an OutOfMemoryError occurs.
 	 */
@@ -249,9 +249,9 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 			memoryReserve[i] = (byte) i;
 		}
 	}
-	
+
-	
+
-	
+
 	/**
 	 * Return whether this throwable was caused by an OutOfMemoryError
 	 * condition.  An exception is deemed to be caused by OutOfMemoryError
@@ -271,9 +271,9 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 		}
 		return false;
 	}
-	
+
-	
+
-	
+
 	/**
 	 * Handler used in modal dialogs by Sun Java implementation.
 	 */
@@ -282,8 +282,8 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 			Application.getExceptionHandler().uncaughtException(Thread.currentThread(), t);
 		}
 	}
-	
+
-	
+
 	/**
 	 * Detect various non-fatal Sun JRE bugs.
 	 * 
@@ -291,32 +291,32 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 	 * @return		whether this exception should be ignored
 	 */
 	private boolean isNonFatalJREBug(Throwable t) {
-		
+
 		// NOTE:  Calling method logs the entire throwable, so log only message here
-		
+
-		
+
 		/*
 		 * Detect and ignore bug 6826104 in Sun JRE.
 		 */
 		if (t instanceof NullPointerException) {
 			StackTraceElement[] trace = t.getStackTrace();
-			
+
 			if (trace.length > 3 &&
 					trace[0].getClassName().equals("sun.awt.X11.XWindowPeer") &&
 					trace[0].getMethodName().equals("restoreTransientFor") &&
-					
+
 					trace[1].getClassName().equals("sun.awt.X11.XWindowPeer") &&
 					trace[1].getMethodName().equals("removeFromTransientFors") &&
-					
+
 					trace[2].getClassName().equals("sun.awt.X11.XWindowPeer") &&
 					trace[2].getMethodName().equals("setModalBlocked")) {
 				log.warn("Ignoring Sun JRE bug (6826104): http://bugs.sun.com/view_bug.do?bug_id=6826104" + t);
 				return true;
 			}
-			
+
 		}
-		
+
-		
+
 		/*
 		 * Detect and ignore bug 6828938 in Sun JRE 1.6.0_14 - 1.6.0_16.
 		 */
@@ -326,26 +326,26 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 			if (elements.length >= 3 &&
 					(buggyClass.equals(elements[0].getClassName()) ||
 							buggyClass.equals(elements[1].getClassName()) ||
-					buggyClass.equals(elements[2].getClassName()))) {
+							buggyClass.equals(elements[2].getClassName()))) {
 				log.warn("Ignoring Sun JRE bug 6828938:  " +
 						"(see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6828938): " + t);
 				return true;
 			}
 		}
-		
+
 		/*
 		 * Detect and ignore bug 6561072 in Sun JRE 1.6.0_?
 		 */
 		if (t instanceof NullPointerException) {
 			StackTraceElement[] trace = t.getStackTrace();
-			
+
 			if (trace.length > 3 &&
 					trace[0].getClassName().equals("javax.swing.JComponent") &&
 					trace[0].getMethodName().equals("repaint") &&
-					
+
 					trace[1].getClassName().equals("sun.swing.FilePane$2") &&
 					trace[1].getMethodName().equals("repaintListSelection") &&
-					
+
 					trace[2].getClassName().equals("sun.swing.FilePane$2") &&
 					trace[2].getMethodName().equals("repaintSelection")) {
 				log.warn("Ignoring Sun JRE bug 6561072 " +
@@ -353,14 +353,14 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 				return true;
 			}
 		}
-		
+
-		
+
 		/*
 		 * Detect and ignore bug 6933331 in Sun JRE 1.6.0_18 and others
 		 */
 		if (t instanceof IllegalStateException) {
 			StackTraceElement[] trace = t.getStackTrace();
-			
+
 			if (trace.length > 1 &&
 					trace[0].getClassName().equals("sun.awt.windows.WComponentPeer") &&
 					trace[0].getMethodName().equals("getBackBuffer")) {
@@ -369,20 +369,20 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 				return true;
 			}
 		}
-		
+
 		/*
 		 * Detect and ignore bug in Sun JRE 1.6.0_19
 		 */
 		if (t instanceof NullPointerException) {
 			StackTraceElement[] trace = t.getStackTrace();
-			
+
 			if (trace.length > 3 &&
 					trace[0].getClassName().equals("sun.awt.shell.Win32ShellFolder2") &&
 					trace[0].getMethodName().equals("pidlsEqual") &&
-					
+
 					trace[1].getClassName().equals("sun.awt.shell.Win32ShellFolder2") &&
 					trace[1].getMethodName().equals("equals") &&
-					
+
 					trace[2].getClassName().equals("sun.awt.shell.Win32ShellFolderManager2") &&
 					trace[2].getMethodName().equals("isFileSystemRoot")) {
 				log.warn("Ignoring Sun JRE bug " +
@@ -390,7 +390,7 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 				return true;
 			}
 		}
-		
+
 		/*
 		 * Detect Sun JRE bug in D3D
 		 */
@@ -401,25 +401,43 @@ public class SwingExceptionHandler implements Thread.UncaughtExceptionHandler, E
 				return true;
 			}
 		}
-		
+
+		/*
+		 * Detect and ignore DnD bug in component tree - related to 6560955 in Sun JRE.
+		 */
+		if (t instanceof NullPointerException) {
+			StackTraceElement[] trace = t.getStackTrace();
+
+			if (trace.length > 2 &&
+					trace[0].getClassName().equals("javax.swing.tree.TreePath") &&
+					trace[0].getMethodName().equals("pathByAddingChild") &&
+
+					trace[1].getClassName().equals("javax.swing.plaf.basic.BasicTreeUI") &&
+					trace[1].getMethodName().equals("getDropLineRect")) {
+
+				log.warn("Ignoring Sun JRE bug updating drop location " +
+						"(see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6560955): " + t);
+				return true;
+			}
+		}
 		return false;
 	}
-	
+
-	
+
 	@SuppressWarnings("unused")
 	private static class InternalException extends Exception {
 		public InternalException() {
 			super();
 		}
-		
+
 		public InternalException(String message, Throwable cause) {
 			super(message, cause);
 		}
-		
+
 		public InternalException(String message) {
 			super(message);
 		}
-		
+
 		public InternalException(Throwable cause) {
 			super(cause);
 		}