Thrown to indicate that a block of code has not been implemented. This exception supplements UnsupportedOperationException by providing a more semantically rich description of the problem.

NotImplementedException represents the case where the author has yet to implement the logic at this point in the program. This can act as an exception based TODO tag. Because this logic might be within a catch block, this exception suports exception chaining.

 public void foo() {
   try {
     // do something that throws an Exception
   } catch (Exception ex) {
     // don't know what to do here yet
     throw new NotImplementedException("TODO", ex);
   }
 }