Question

Firstly apologies if this a very basic question, I’m just curious to know the difference between the following string definitions

String x= "hello";
String y = new String("hello");

I knew that in java String is a Class its neither a primitive nor a Wrapper(Correct me if this a misconception). Consider a class A, I’ve seen the following declarations for any class so far. i think A c; is valid and A a = new A(); is also valid. I’m confused with A a ="xyz"; this is how we declared a String as in above first type of definition. I’m sure that the above two definitions are absolutely different, like if i say x==y it returns false. I understand that y is the reference to the String object. What is x there, how is it stored in memory, interestingly i found that both x and y can access all the methods of String class.

Then what is the advantage of one over other.Can i know the applicability of each.

Answer 1

From the 2nd edition of Joshua Bloch’s “Effective Java”:

String s = new String("stringette");// DON'T DO THIS!

The statement creates a new String instance each time it is executed,
and none of those object creations is necessary. The argument to the
String constructor (“stringette”) is itself a String instance,
functionally identical to all of the objects created by the
constructor. If this usage occurs in a loop or in a frequently invoked
method, millions of String instances can be created needlessly. The
improved version is simply the following:

String s = "stringette";