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.Write a method that prints outthe stored String.Create a try-catch clause to exercise your newexception.Commentll Write a class with a method that throws an exception of the type created inExercise 2.Try compiling it without an exception specification to see what thecompiler says.Add the appropriate exception specification.Try out your classand its exception inside a try-catch clause.Commentll Define an object reference and initialize it to null.Try to call amethod through this reference.Now wrap the code in a try-catch clause tocatch the exception.Commentll Create a class with two methods, f( ) and g( ).Ing( ), throw an exception of a new type that you define.Inf( ), call g( ), catch its exception and, in thecatch clause, throw a different exception (of a second type that youdefine).Test your code in main( ).Commentll Create three new types of exceptions.Write a class with a method thatthrows all three.In main( ), call the method but only use a singlecatch clause that will catch all three types of exceptions.Commentll Write code to generate and catch an ArrayIndexOutOfBoundsException.Commentll Create your own resumption-like behavior using a while loop thatrepeats until an exception is no longer thrown.Commentll Create a three-level hierarchy of exceptions.Now create a base-class Awith a method that throws an exception at the base of your hierarchy.Inherit B from A and override the method so it throws an exceptionat level two of your hierarchy.Repeat by inheriting class C fromB.In main( ), create a C and upcast it to A,then call the method.Commentll Demonstrate that a derived-class constructor cannot catch exceptions thrownby its base-class constructor.Commentll Show that OnOffSwitch.java can fail by throwing aRuntimeException inside the try block.Commentll Show that WithFinally.java doesn’t fail by throwing aRuntimeException inside the try block.Commentll Modify Exercise 6 by adding a finally clause.Verify yourfinally clause is executed, even if a NullPointerException isthrown.Commentll Create an example where you use a flag to control whether cleanup code iscalled, as described in the second paragraph after the heading“Constructors.” Commentll Modify StormyInning.java by adding an UmpireArgumentexception type, and methods that throw this exception.Test the modifiedhierarchy.Commentll Remove the first catch clause in Human.java and verify that the codestill compiles and runs properly.Commentll Add a second level of exception loss to LostMessage.java so that theHoHumException is itself replaced by a third exception.Commentll In Chapter 5, find the two programs called Assert.java and modifythese to throw their own type of exception instead of printing toSystem.err.This exception should be an inner class that extendsRuntimeException.Commentll Add an appropriate set of exceptions to c08:GreenhouseControls.java.CommentlThe C programmer can look up the return value of printf( ) for an example of this.This is a significant improvement over C++ exception handling, which doesn’t catch violations of exception specifications until run time, when it’s not very useful.C++ exception handling does not have the finally clause because it relies on destructors to accomplish this sort of cleanup.A destructor is a function that’s always called when an object becomes unused.You always know exactly where and when the destructor gets called.C++ has automatic destructor calls, but Delphi’s Object Pascal versions 1 and 2 do not (which changes the meaning and use of the concept of a destructor for that language).ISO C++ added similar constraints that require derived-method exceptions to be the same as, or derived from, the exceptions thrown by the base-class method.This is one case in which C++ is actually able to check exception specifications at compile-time.In C++, a destructor would handle this for you [ Pobierz całość w formacie PDF ]
