devxlogo

Destructors

Destructors

Question:
In Java, how do I achieve the same functionality which is provided byclass destructors in C++? Is there a destructor method in Java?

Answer:
Java does not possess the concept of a destructor. In C++, you needto perform explicity memory management, invoking new to allocatememory and invoking delete to free memory. The C++ new operator createsnew objects and invokes their constructors as part of theinitialization process. Java works in much the same way. The deleteoperator frees the memory used by an object, invoking its destructoras part of the process. Java does not possess this feature. Instead,Java frees memory for you on its own.

Java is a garbage collected language. This means that part of theruntime system is dedicated to finding objects that are no longerreferenced by any part of a program and freeing up the memory.Therefore, destructors are not needed.

The closest thing to adestructor in the Java language is the finalize() method defined inthe Object class. The finalize() method of an object is invoked bythe garbage collector prior to freeing its memory. However, noguarantees are made about which thread will invoke finalize() or exactlywhen it will be invoked. The purpose of the finalize() method is toallow objects to free resources that cannot be freed by the garbagecollector (usually native resources such as file descriptors andgraphics contexts). As a consequence, you normally only implement thefinalize() method when you are using native code in a class.

devx-admin

Share the Post: