Bug 131516 [Browser] NullPointerException in MozillaBrowser.openURL()
In MozillaBrowser.openURL() there is no check to see if the argument url2 is null before calling url2.toExternalForm(). So passing in null to this method results in a NullPointerException.
bundles/org.eclipse.ui.browser/src/org/eclipse/ui/internal/browser/browsers/MozillaBrowser.java
protected static final int DELAY = 5000;
	protected long browserFullyOpenedAt = 0;
	private BrowserThread lastBrowserThread = null;
	protected String executable;
	
	protected boolean firstLaunch = true;
	/**
	 * Constructor
	 * 
	 * @executable executable filename to launch
	 * @executableName name of the program to display when error occurs
	 */
	public MozillaBrowser(String id, String executable) {
		super(id);
		this.executable = executable;
	}
	/*
	 * @see IBrowser#displayURL(String)
	 */
	public void openURL(URL url2) {
		String url = url2.toExternalForm();
		if (lastBrowserThread != null)
			lastBrowserThread.exitRequested = true;
		lastBrowserThread = new BrowserThread(url);
		lastBrowserThread.setDaemon(true);
		lastBrowserThread.start();
	}
	private class BrowserThread extends Thread {