blankfinal.java

Java编程思想 第六课 全源码

//: c06:BlankFinal.java
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// "Blank" final data members.

class Poppet {
	 Poppet(){
		System.out.println("Use the class Poppet"); 
	}
}

class BlankFinal {
  final int i = 0; // Initialized final
  final int j; // Blank final
  final Poppet p; // Blank final reference
  // Blank finals MUST be initialized
  // in the constructor:
  BlankFinal() {
    j = 1; // Initialize blank final
    p = new Poppet();
  }
  BlankFinal(int x) {
    j = x; // Initialize blank final
    p = new Poppet();
  }
  public static void main(String[] args) {
    BlankFinal bf = new BlankFinal();
    BlankFinal bf1 = new BlankFinal(2);
    System.out.println(" bf: " + bf + "\nbf1: " + bf1);
  }
} ///:~