![]() accessEnclosingClass() is able to access EnclosingClass's s field and call its m1() method, even though both have been declared private.prefix because accessEnclosingClass() is declared static. m2()'s invocation of SMClass's accessEnclosingClass() method requires the SMClass.SMClass declares class method accessEnclosingClass() and instance method accessEnclosingClass2(). Listing 1 declares a top-level class named EnclosingClass with class field s, class methods m1() and m2(), and static member class SMClass. S = "Called from SMClass's accessEnclosingClass() method" Declaring a static member class (EnclosingClass.java, version 1) To demonstrate, Listing 1 declares an EnclosingClass with a nested SMClass. However, it can access the enclosing class's static fields and invoke its static methods, even those members that are declared private. Enclosure and access rulesĪlthough it is enclosed, a static member class cannot access the enclosing class's instance fields and invoke its instance methods. Since all of these elements belong to class C, it is known as the enclosing class. The static field f, static method m(), and the static initializer are also members of C. This example introduces top-level class C with static field f, static method m(), a static initializer, and static member class D. Here's an example of a static member class declaration: Formally known as static member classes, these are nested classes that you declare at the same level as these other static entities, using the static keyword. Now you'll learn how to declare static classes. In Class and object initialization in Java, you learned how to declare static initializers as members of a class. In my Java 101 tutorial Classes and objects in Java, you learned how to declare static fields and static methods as members of a class. Avoid memory leaks in nested classesĪlso see the Java tip associated with this tutorial, where you'll learn why nested classes are vulnerable to memory leaks. ![]() ![]() In this tutorial you'll learn how to work with static member classes and the three types of inner classes in your Java code. Inner classes are non-static member classes, local classes, or anonymous classes. In Java, nested classes are categorized as either static member classes or inner classes. This works because the two are closely related. Rather than pollute the top-level class's namespace, you could declare the iterator class as a member of the resizable array collection class. For example, say you have a non-nested class (also known as a top-level class) that stores objects in a resizable array, followed by an iterator class that returns each object. Nesting classes is one way to better organize your code. Nested classes are classes that are declared as members of other classes or scopes.
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