Difference between throwing new RuntimeException vs casting cause to RuntimeException

Question

Is there a difference between

} catch (ExceptionType1 e) {
    throw new RuntimeException(e);
}

and

} catch (ExceptionType1 e) {
    throw (RuntimeException) e.getCause();
}

If there is a difference, what should I be checking for in ExceptionType1 to figure out which one is better?

Answer 1

There are a number of differences:

 throw new RuntimeException(e);

This wraps whatever exception e in a new RuntimeException , and throw this RunTimeException

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On the other hand:

throw (RuntimeException) e.getCause();

This tries to cast the cause of whatever exception e to a RuntimeException . Main differences are:

• You lose the detail of the original exception e , as you only attempt to throw its cause (which might be null)
• The cause might not inherit from RuntimeException and may not be castable, in which case a ClassCastException will occur.