Bug 25845 Support for manually attaching source to a class path container
From Dejan: There is a work item on the ability to manually attach source to classpath entries managed by classpath container. We discussed it and we have workable options but we would like if we can have it by M3 because we want to start self-hosting using classpath containers ourselves.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
private IStatusChangeListener fContext;
	
	private StringButtonDialogField fFileNameField;
	private SelectionButtonDialogField fInternalButtonField;
	
	
	private boolean fIsVariableEntry;
	
	private IStatus fNameStatus;
		
	private IPath fJARPath;
	
	/**
	 * The file to which the archive path points to.
	 * Only set when the file exists.
	 */
	private File fResolvedFile; 
	/**
	 * The path to which the archive variable points.
	 * Null if invalid path or not resolvable. Must not exist.
	 */	
	private IPath fFileVariablePath;