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  1. package chapter10;
  2.  
  3. interface Incrementable {
  4.     void increment();
  5. }
  6.  
  7. class Callee1 implements Incrementable {
  8. 	private int i = 0;
  9.  
  10. 	public void increment() {
  11. 		i++;
  12. 		System.out.println(i);
  13. 	}
  14. }
  15.  
  16. class MyIncrement {
  17. 	public void increment() {
  18. 		System.out.println("Other operation");
  19. 	}
  20.  
  21. 	static void f(MyIncrement mi) {
  22. 		mi.increment();
  23. 	}
  24. }
  25.  
  26. class Callee2 extends MyIncrement {
  27. 	private int i = 0;
  28.  
  29. 	public void increment() {
  30. 		super.increment();
  31. 		i++;
  32. 		System.out.println(i);
  33. 	}
  34.  
  35. 	private class Closure implements Incrementable {
  36. 		public void increment() {
  37. 			Callee2.this.increment();
  38. 		}
  39. 	}
  40.  
  41. 	Incrementable getCallbackReference() {
  42. 		return new Closure();
  43. 	}
  44. }
  45.  
  46. class Caller {
  47. 	private Incrementable callbackReference;
  48.  
  49. 	Caller(Incrementable cbh) {
  50. 		callbackReference = cbh;
  51. 	}
  52.  
  53. 	void go() {
  54. 		callbackReference.increment();
  55. 	}
  56. }
  57.  
  58. public class CallBacks {
  59.  
  60. 	public static void main(String[] args) {
  61. 		Callee1 c1 = new Callee1();
  62. 		Callee2 c2 = new Callee2();
  63. 		MyIncrement.f(c2);
  64. 		Caller caller1 = new Caller(c1);
  65. 		Caller caller2 = new Caller(c2.getCallbackReference());
  66. 		caller1.go();
  67. 		caller1.go();
  68. 		caller2.go();
  69. 		caller2.go();
  70. 	}
  71. }
  72.  
Compilation error #stdin compilation error #stdout 0s 0KB
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stdin
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Standard input is empty
compilation info 
Main.java:58: error: class CallBacks is public, should be declared in a file named CallBacks.java
public class CallBacks {
       ^
1 error
stdout
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Standard output is empty
https://ideone.com/YjjKuG
language:
Java (HotSpot 12)
created:
12 years ago
visibility:
public

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