Bug 36867 [Import/Export] Zip export dialog not append .zip if there is already an extension
Sometimes, when the Jar export dialog doesn't have the options I want, I use the zip export dialog to build a jar. Unfortunately, if I specify a file name of foo.jar, the zip export dialog insists on adding ".zip" to the end of the file name. Would it be possible to make it so ".zip" is not automatically added if there is already an extension on the file name (or specifically if ".jar" is there)? Or could there be a checkbox added on the export dialog to turn off the automatic appending of .zip?
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/wizards/datatransfer/WizardZipFileResourceExportPage1.java
compressContentsCheckbox =
			new Button(optionsGroup, SWT.CHECK | SWT.LEFT);
		compressContentsCheckbox.setText(DataTransferMessages.getString("ZipExport.compressContents")); 
		compressContentsCheckbox.setFont(font);
		createDirectoryStructureOptions(optionsGroup, font);
		
		createDirectoryStructureButton.setSelection(true);
		createSelectionOnlyButton.setSelection(false);
		compressContentsCheckbox.setSelection(true);
	}
	/**
	 * Returns a boolean indicating whether the directory portion of the
	 * passed pathname is valid and available for use.
	 */
	protected boolean ensureTargetDirectoryIsValid(String fullPathname) {
		int separatorIndex = fullPathname.lastIndexOf(File.separator);
		if (separatorIndex == -1) 
			return true;
		return ensureTargetIsValid(
			new File(fullPathname.substring(0, separatorIndex)));
	}
	/**
	 * Returns a boolean indicating whether the passed File handle is
	 * is valid and available for use.
	 */
	protected boolean ensureTargetFileIsValid(File targetFile) {
		if (targetFile.exists() && targetFile.isDirectory()) {
			displayErrorDialog(DataTransferMessages.getString("ZipExport.mustBeFile")); 
			giveFocusToDestination();
			return false;