[java] What is the standard exception to throw in Java for not supported/implemented operations?

In particular, is there a standard Exception subclass used in these circumstances?

Differentiate between the two cases you named:

• To indicate that the requested operation is not supported and most likely never will, throw an UnsupportedOperationException.

• To indicate the requested operation has not been implemented yet, choose between this:

  1. Use the NotImplementedException from apache commons-lang which was available in commons-lang2 and has been re-added to commons-lang3 in version 3.2.

  2. Implement your own NotImplementedException.

  3. Throw an UnsupportedOperationException with a message like "Not implemented, yet".

If you create a new (not yet implemented) function in NetBeans, then it generates a method body with the following statement:

throw new java.lang.UnsupportedOperationException("Not supported yet.");

Therefore, I recommend to use the UnsupportedOperationException.

If you want more granularity and better decription, you could use NotImplementedException from commons-lang

Warning: Available before versions 2.6 and after versions 3.2, only.