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Instead of catching the exception in mediumJob, we could catch it at a higher level, like main:

Here, the exception will happen in line 8. Since there is no try block around line 8 in mediumJob, we immediately exit that function and jump back to bigJob. bigJob called mediumJob on line 14, so that location is checked for a try block. Because there is none, we exit bigJob without running lines 15-16 and jump back to main.

Finally, in main where we called bigJob (line 21) the code is inside of a try. So execution in the try stops (line 22 never runs) and jumps to the start of the attached catch. Lines 24-25 then run.

A try...catch in mediumJob() or bigJob() would have caught the exception and stopped it from passing up on to higher levels. But if they do not want to try to handle the exception, no extra code is needed in them to allow the exception to pass up.

When an exception passes up through levels of function calls like this, we say it is being propagated up the call stack. .