Bug 8476 JAR Packager: Make main class field editable
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/JarManifestWizardPage.java
Label spacer= new Label(parent, SWT.NONE);
		GridData data= new GridData();
		data.horizontalAlignment= GridData.FILL;
		data.verticalAlignment= GridData.BEGINNING;
		spacer.setLayoutData(data);
	}
	/**
	 * Returns the resource for the specified path.
	 *
	 * @param path	the path for which the resource should be returned
	 * @return the resource specified by the path or <code>null</code>
	 */
	protected IResource findResource(IPath path) {
		IWorkspace workspace= JavaPlugin.getWorkspace();
		IStatus result= workspace.validatePath(
							path.toString(),
							IResource.ROOT | IResource.PROJECT | IResource.FOLDER | IResource.FILE);
		if (result.isOK() && workspace.getRoot().exists(path))
			return workspace.getRoot().findMember(path);
		return null;
	}
	protected IPath getPathFromString(String text) {
		return new Path(text).makeAbsolute();
	}
	/**
	 * Creates a selection dialog that lists all packages under the given package 
	 * fragment root.
	 * The caller is responsible for opening the dialog with <code>Window.open</code>,
	 * and subsequently extracting the selected packages (of type
	 * <code>IPackageFragment</code>) via <code>SelectionDialog.getResult</code>.