Argument must be final to use inside anonymous inner class : Anonymous inner class « Class Definition « Java Tutorial

1. Java Tutorial
2. Class Definition
3. Anonymous inner class

public class MainClass {
  public A dest(final String dest) {
    return new A() {
      private String label = dest;

      public String readLabel() {
        return label;
      }
    };
  }

  public static void main(String[] args) {
    MainClass p = new MainClass();
    A d = p.dest("A");
  }
}

interface A {
  String readLabel();
}