Bug 13799 JAR exporter exports class files from output folder
There was a problem with the output folder not being detected as such.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/JarFileExportOperation.java
private MultiStatus fProblems;
	
	/**
	 * Creates an instance of this class.
	 *
	 * @param	jarPackage	the JAR package specification
	 * @param	parent	the parent for the dialog,
	 * 			or <code>null</code> if no dialog should be presented
	 */
	public JarFileExportOperation(JarPackageData jarPackage, Shell parent) {
		this(new JarPackageData[] {jarPackage}, parent);
	}
	/**
	 * Creates an instance of this class.
	 *
	 * @param	descriptions	an array with JAR package descriptions
	 * @param	parent			the parent for the dialog,
	 * 			or <code>null</code> if no dialog should be presented
	 */
	public JarFileExportOperation(JarPackageData[] jarPackages, Shell parent) {
		this(parent);
		fJarPackages= jarPackages;
	}
	/**
	 * Adds a new warning to the list with the passed information.
	 * Normally the export operation continues after a warning.
	 * @param	message		the message
	 * @param	exception	the throwable that caused the warning, or <code>null</code>
	 */
	private JarFileExportOperation(Shell parent) {