For object references, the == operator returns true only if both references are to the same object. : Comparison Operators « Operators « SCJP

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2. Operators
3. Comparison Operators

public class MainClass {
  public static void main(String[] argv) {
    Integer x1 = new Integer(5);
    Integer x2 = x1;
    Integer x3 = new Integer(5);
    if (x1 == x2)
      System.out.println("x1 eq x2");
    if (x2 == x3)
      System.out.println("x2 eq x3");

  }
}

x1 eq x2