SCJP 5 : Chapter 1. Declarations, Initialization and Scoping (Part-6)
Given a set of classes and superclasses, develop constructors for one or more of the classes. Given a class declaration, determine if a default constructor will be created, and if so, determine the behavior of that constructor. Given a nested or non-nested class listing, write code to instantiate the class.
Creating Inner Classes Instances
Non-static inner classes have a hidden reference to the enclosing class instance. This means you must have an instance of the enclosing class to create the inner class. You also have to use a special "new" function that correctly initializes the hidden reference to the enclosing class. The special "new" function is a member of the enclosing class.
public class InnerClassTest { .
.....public class ReallyInner {
......}
}
|
InnerClassTest o = new InnerClassTest();
InnerClassTest.ReallyInner i = o.new ReallyInner();
|
or
| InnerClassTest.ReallyInner i = new InnerClassTest().new ReallyInner(); |
Example:
public class InnerClassTest {
......public void foo() {
............System.out.println("Outer class");
......}
......public class ReallyInner {
............public void foo() {
..................System.out.println("Inner class");
.............}
public void test() {
..................this.foo();
..................InnerClassTest.this.foo();
............}
......}
............public static void main(String[] args) {
.................InnerClassTest.ReallyInner i = new
....................InnerClassTest().new ReallyInner();
....................i.test();
...........}
}
|
Output:
Inner class
Outer class
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Author: Mikalai Zaikin. Please Click Here to visit Authors site for any updates and changes to the study notes.
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