final in Java

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class A {
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  private int i;
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  A(int ii) {
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    i = ii;
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  }
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}
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public class MainClass {
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  private final int i = 0; // Initialized final
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  private final int j; // Blank final
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  private final A a; // Blank final reference
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  // Blank finals MUST be initialized in the constructor:
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  public MainClass() {
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    j = 1; // Initialize blank final
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    a = new A(1); // Initialize blank final reference
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  }
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  public MainClass(int x) {
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    j = x; // Initialize blank final
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    a = new A(x); // Initialize blank final reference
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  }
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  public static void main(String[] args) {
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    new MainClass();
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    new MainClass(47);
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  }
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}

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class A {
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  final void meth() {
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    System.out.println("This is a final method.");
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  }
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}
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class B extends A {
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  void meth() { // ERROR! Can't override.
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    System.out.println("Illegal!");
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  }
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}