code: def find_jar(jar_name, root_path=None):
      
      jar_name = os.path.basename(jar_name)
      root = root_path or os.getcwd()
      paths = (root, os.path.join(root, "build"), "/usr/share/java")
      for p in paths:
          p = os.path.join(p, jar_name)
          if os.path.exists(p):
              return p
      return None
docs: Look for the named jar in:
  
      #. ``root_path``, if specified
      #. working directory -- ``PWD``
      #. ``${PWD}/build``
      #. ``/usr/share/java``
  
      Return the full path of the jar if found; else return :obj:`None`.