Creation date: 25 March, 2011

String equality

Try to predict the result of the following code.

  String s = "test";
  System.out.println(s.equals("test"));
  System.out.println(s == "test");
  System.out.println(s == new String("test"));

I think the result of s.equals("test") is obvious. Yes, it's true (I mean result). But the result of s == "test" is also true. Because all String objects are immutable, before creation of new String Java looks at pool and tries to find the creating string. If it founds, it sets reference of found string to variable. Java does it to save memory. That's why the equality s == "test" is true. The equality check s == new String("test") returns false because in this case we force Java to create a new instance of String object.

Author: Jafar N.Aliyev (Jsoft)

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