Difference (Beginning Java forum at Coderanch)

Post by: Saravanan Jothimani , Greenhorn

Feb 26, 2005 05:49:00

Hi,

Please give me a detailed difference between String and StringBuffer

Thanks in Advance

Saravanan

Post by: Liam Tiarnach , Ranch Hand

Feb 26, 2005 05:56:00

Originally posted by Saravanan Jothimani:
Hi,

Please give me a detailed difference between String and StringBuffer

Thanks in Advance

Saravanan

Hmmm... to much typing...

how about this link...

http://java.sun.com/docs/books/tutorial/java/data/strings.html

from the Sun's Java Tutorial...

Post by: K Riaz , Ranch Hand

Feb 26, 2005 11:24:00

String is immutable (it can't change) whilst a StringBuffer is not (it can change). Its a popular inteview question. When you invoke methods on a String object, you may think you can edit it, but you are actually getting a new String object back.

Post by: Saravanan Jothimani , Greenhorn

Feb 27, 2005 22:16:00

class stringbufferexample
{
String str = "TATA";
StringBuffer strbuff = new StringBuffer();
String strone = "Infotech";
StringBuffer strbuffone = strbuff.append("ICICI");
public void print()
{
System.out.println(str);
System.out.println(strone);
System.out.println(strbuff);
System.out.println(strbuffone);
}
public static void main(String args[])
{
stringbufferexample sbe = new stringbufferexample();
sbe.print();
}
}

My out put is

TATA
Infotech
ICICI
ICICI

Why I am getting the output like this
System.out.println(str); - TATA -Correct
System.out.println(strone); - Infotech - Correct
System.out.println(strbuff); - ?. - I have createad an object
System.out.println(strbuffone); -ICICI - Correct - Because I am appending a string.

Pls help me out
I am little bit confused.

Thanks in Advance

Saravanan

Post by: Marilyn de Queiroz , Sheriff

Feb 27, 2005 22:36:00

The key is in this line
StringBuffer strbuffone = strbuff.append("ICICI");
Although you are assigning the result to strbuffone, you have also changed the original strbuff object. When you print strbuff, you get the modified StringBuffer object, the one with "ICICI" appended.

Post by: David Harkness , Ranch Hand

Feb 27, 2005 22:58:00

The reason StringBuffer.append() is confusing is that the StringBuffer it returns is not a new StringBuffer with the text appended but the same StringBuffer to support method chaining.

Post by: Saravanan Jothimani , Greenhorn

Feb 28, 2005 00:23:00

Thanks

Post by: Layne Lund , Ranch Hand

Feb 28, 2005 11:25:00

You may also want to look at this.

Layne

Post by: Saravanan Jothimani , Greenhorn

Mar 01, 2005 06:55:00

Hi,

If I am using
Final StringBuffer s = new StringBuffer ("Hello");, Can I append this object s using append();

Thanks in Advance

Saravanan

Post by: Ernest Friedman-Hill , Sheriff

Mar 01, 2005 08:32:00

Originally posted by Saravanan Jothimani:

If I am using
Final StringBuffer s = new StringBuffer ("Hello");, Can I append this object s using append();

Yes. The variable "s" is final -- i.e., it can't be made to point to another StringBuffer -- but the StringBuffer itself is mutable. There's no equivalent to C++'s "const" in Java.

Post by: Saravanan Jothimani , Greenhorn

Mar 02, 2005 01:34:00

Thanks Ernest Friedman-Hill

Regards

Saravanan