SpMapper | simple Sharepoint Lists object mapper | Content Management System library

Using a try-finally statement without declaring a catch statement is legal.

From the JLS :

14.20.2. Execution of try-finally and try-catch-finally

A try statement with a finally block is executed by first executing the try block. Then there is a choice:

If execution of the try block completes normally, then the finally block is executed, and then there is a choice:

If the finally block completes normally, then the try statement completes normally.

If the finally block completes abruptly for reason S, then the try statement completes abruptly for reason S.

You said :

we are neither catching a exception nor cleaning up code in finally block. If thats the case, why does JAVA has not considered a compile time check on this ?

What you write in the finally statement is of course at the hand of the developer.
Having a empty finally statement is useless but it is the same thing that having an empty if or for statement.
These are helpless but the compiler will not complain about it as it stays valid code in terms of compilation.
However, IDEs could emit warnings about it to point bad smells.