IClasspathEntry entry= JavaCore.getClasspathVariable(varName); if (entry == null) {
IPath entryPath= JavaCore.getClasspathVariable(varName); if (entryPath == null) {
	private IPath chooseExtJar() {		String varName= fVariableField.getText();		IClasspathEntry entry= JavaCore.getClasspathVariable(varName);		if (entry == null) {			return null;		}		IPath entryPath= entry.getPath();		String lastUsedPath= entryPath.append(fExtensionField.getText()).removeLastSegments(1).toOSString();				FileDialog dialog= new FileDialog(getShell(), SWT.SINGLE);		dialog.setFilterExtensions(new String[] {"*.jar;*.zip"});		dialog.setFilterPath(lastUsedPath);		String res= dialog.open();		if (res == null) {			return null;		}		IPath resPath= new Path(res);		if (!entryPath.isPrefixOf(resPath)) {			return new Path(resPath.lastSegment());		} else {			return resPath.removeLastSegments(entryPath.segmentCount());		}	}