Test.java

public class Test {
  public static void main(String[] args) {

    // Primitives
    int a = 10;
    int b = 10;

    System.out.println("a: " + a); // 10
    System.out.println("b: " + b); // 10
    System.out.println("a == b: " + (a == b)); // true

    // Objects
    Integer c = new Integer(10);
    Integer d = new Integer(10);

    System.out.println("c: " + c); // 10
    System.out.println("d: " + d); // 10
    System.out.println("c == d: " + (c == d)); // false
    System.out.println("c.equals(d): " + (c.equals(d))); // true

    // More Objects
    Integer e = new Integer(1000);
    Integer f = new Integer(1000);

    System.out.println("e: " + e); // 10
    System.out.println("f: " + f); // 10
    System.out.println("e == f: " + (e == f)); // false
    System.out.println("e.equals(f): " + (e.equals(f))); // true

    // Special Objects?
    Integer g = 20;
    Integer h = 20;

    System.out.println("g: " + g); // 20
    System.out.println("h: " + h); // 20
    System.out.println("g == h: " + (g == h)); // true
    System.out.println("g.equals(h): " + (g.equals(h))); // true

    // More Use of the Integer Cache
    Integer i = Integer.valueOf(20);
    Integer j = Integer.valueOf(20);

    System.out.println("i: " + i); // 20
    System.out.println("j: " + j); // 20
    System.out.println("i == j: " + (i == j)); // true
    System.out.println("i.equals(j): " + (i.equals(j))); // true
  }
}