Android™ How to Program, Second Edition

Stack Unwinding

In main, the try block (lines 8–11) calls method1 (declared at lines 35–38), which in turn calls method2 (declared at lines 41–44), which in turn calls method3 (declared at lines 47–50). Line 49 of method3 throws an Exception object—this is the throw point. Because the throw statement at line 49 is not enclosed in a try block, stack unwinding occurs—method3 terminates at line 49, then returns control to the statement in method2 that invoked method3 (i.e., line 43). Because no try block encloses line 43, stack unwinding occurs again—method2 terminates at line 43 and returns control to the statement in method1 that invoked method2 (i.e., line 37). Because no try block encloses line 37, stack unwinding occurs one more time—method1 ...