Different languages have different exception handing optimizations. A Java version of the example can run very slow or very fast, depending on how clever you are.
When a new RuntimeException is thrown half the time, the example runs about 650 times slower when compared to a function which adds up the integers without using exceptions. If I define an exception subclass which doesn't fill in the stack trace, then it runs about 10 times slower. If I throw a singleton exception instance, then the performance is identical.
The reason why the performance is identical is because HotSpot inlined the code and converted the immediate throw-catch into a simple goto. It wasn't smart enough to see that the stack trace wasn't needed, nor was it smart enough to see that allocating new instances wasn't needed either. I had to make those transformations manually.
When a new RuntimeException is thrown half the time, the example runs about 650 times slower when compared to a function which adds up the integers without using exceptions. If I define an exception subclass which doesn't fill in the stack trace, then it runs about 10 times slower. If I throw a singleton exception instance, then the performance is identical.
The reason why the performance is identical is because HotSpot inlined the code and converted the immediate throw-catch into a simple goto. It wasn't smart enough to see that the stack trace wasn't needed, nor was it smart enough to see that allocating new instances wasn't needed either. I had to make those transformations manually.