title: What should be the design/Pattern for adding/deleting some piece of Code in the existing one
body: <p>I got a requirement in <strong>JAVA PROJECT</strong> which contains a massive <em>adding</em> and <em>deleting</em> source codes from the existing working copy. There is no other way out. As per design contract, I must not modify the source code , so I thought of inherit the features, <strong><em>but is it the only way to do it?</em></strong> Because it is around 2000+ files changes and each file inheritance is not possible because of Access Specifiers and finals in JAVA.</p>
  
  <p>EXAMPLE:
  Consider a File named MenuManager.java is having a method which adds 10 Menus in the MenuBar.Now as per my requirement I need to remove 5 menus from the existing one and add newly defined(by me) 3 Menus into the same MenuBar.
  So easiest option is override the method but what if this type of features changes is there for the entire source code</p>