// innerclasses/LocalInnerClass.java // (c)2017 MindView LLC: see Copyright.txt // We make no guarantees that this code is fit for any purpose. // Visit http://OnJava8.com for more book information. // Holds a sequence of Objects interface Counter { int next(); } public class LocalInnerClass { private int count = 0; Counter getCounter(final String name) { // A local inner class: class LocalCounter implements Counter { public LocalCounter() { // Local inner class can have a constructor System.out.println("LocalCounter()"); } @Override public int next() { System.out.print(name); // Access local final return count++; } } return new LocalCounter(); } // Repeat, but with an anonymous inner class: Counter getCounter2(final String name) { return new Counter() { // Anonymous inner class cannot have a named // constructor, only an instance initializer: { System.out.println("Counter()"); } @Override public int next() { System.out.print(name); // Access local final return count++; } }; } public static void main(String[] args) { LocalInnerClass lic = new LocalInnerClass(); Counter c1 = lic.getCounter("Local inner "), c2 = lic.getCounter2("Anonymous inner "); for(int i = 0; i < 5; i++) System.out.println(c1.next()); for(int i = 0; i < 5; i++) System.out.println(c2.next()); } } /* Output: LocalCounter() Counter() Local inner 0 Local inner 1 Local inner 2 Local inner 3 Local inner 4 Anonymous inner 5 Anonymous inner 6 Anonymous inner 7 Anonymous inner 8 Anonymous inner 9 */