This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
The String class represents character strings. All string literals in Java programs, such as "prasad", are implemented as instances of this class.
Strings are constant; their values cannot be changed after they are created. String buffers support mutable strings. Because String objects are immutable they can be shared. For example:
String str = "prasad";
This creats a string literal, sets it's contents to "prasad" and pases the reference to that literal back to your variable [str].
String str = new str("prasad");
creates a string literal and sets contents to "prasad" (just like above). But a new string is created and the reference to that literal is passed to it. THEN that new string's referenc is passed to your variable [str].
Since TWO string literals are created in the second example, use the first one in your programs.
The explaination lies in understanding the difference between the comparison of an object reference and an object value. This little program explains it in code. Java will set name1 and name2 to the same object reference. Therefore, the first "if" statement evaluates to true, because the "==" is testing that the *references* are the same. However, name3 creates a brand new object with its own object reference. Therefore, the second "if" statement fails because the *references* are different. The third "if" statement evaluates to true because that statement is checking the contents of the String variables, not the references.