SaveAllAction.class is missing in this org.eclipse.ui.workbench Plugin. I found one doc, but I didn't understand, what they are used as the alternate.
SaveAllAction
was an internal class which you should not have been using. It was removed long ago in one of the Eclipse 3 releases.
The current equivalent is the org.eclipse.ui.file.saveAll
command. You can execute this command using something like:
IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
IHandlerServicer handler = window.getService(IHandlerService.class);
handler.executeCommand("org.eclipse.ui.file.saveAll", null);