String comparison doesn’t work for variables. In fact, only variables referencing the same string will work. The String class has an intern method, which lets you compare two variables. This intern method returns a canonical representation for the string object. You can compare interned Strings using == operator. In this code, (one_string==another_one_string) will not return true:

 String one_string = "one";String another_one_string = "one";

Using == operator for String comparison will return true only if both one_string and another_one_string have references to the same String object. So, if one_string and another_one_string are strings such that one_string equals (another_one_string ) returns true, it is guaranteed that (one_string.intern() == another_one_string.intern()) will return true.