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StringBuffer Q

Kedar Dravid
Ranch Hand

Joined: May 28, 2004
Posts: 333
Consider the code below:

class Q53
public static void main(String [] args)
java.lang.StringBuffer sb; //1
sb = new java.lang.StringBuffer().append("Hello").append("World"); //2
System.out.println(sb. substring(5,10).toString());

O/p: World

My question: Isn't sb initialised to null on Line 1?
So, by the end of line 2, isn't content of sb "nullHelloWorld"?
Nathaniel Stoddard
Ranch Hand

Joined: May 29, 2003
Posts: 1258
Negative, blue leader!

Remember that automatic (a.k.a. local) variables are not initialized when declared, as member and class variables are. So, though you've declared it, it isn't even null (it's undefined). Furthermore, new StringBuffers start out with an empty buffer, not a buffer of "null". So, new StringBuffer().toString().equals("") would return true.

subject: StringBuffer Q