Strings and StringBuffer

[nivya]

HI EVERYBODY
This is nivvi, i am new to this. I have doubt regarding strings and stringbuffers.can i use srtingbuffers instead of strings?if so, then which performance is better ?i mean working with strings is better one or stringbuffer is better one for increasing the performance of the progam.

[Tony Smith]

You posted in the wrong forum. Please read the rules first. Use strings, unless you have reason to use stringbuffer.

[Bear Bibeault]

"nivvi",

There aren't many rules that you need to worry about here on the Ranch, but one that we take very seriously regards the use of proper names. Please take a look at the JavaRanch Naming Policy and adjust your display name to match it.

In particular, your display name must be a first and a last name separated by a space character, and must not be obviously fictitious.

Thanks!
bear
JavaRanch Sheriff

[fred rosenberger]

I think the answer to your question, like most software issues, is "it depends".

it depends on HOW you are using the objects, and WHAT you are doing with them. There are situation where one is perferable over the other, and vice versa.

[Peter Chase]

As others have said already, String and StringBuffer are quite different, so there are not all that many situations where you could actually swap one for the other.

Note, though, that StringBuffer is mostly superceded by StringBuilder, in Java 5 onwards. You should not use StringBuffer in new code, but instead should use StringBuilder.

The reason for preferring StringBuilder is that it is not encumbered with pointless synchronisation. Very few uses of StringBuffer actually made use of its synchronisation, but all suffered the performance costs of it.

As a beginner, you don't really need to understand the paragraph above. Just remember that, if you are writing for Java 5 or newer, use StringBuilder.

[Rob Spoor]

If you have to do a lot of string concatenation (string1 + string2), use StringBuilder instead of String. If you don't, it's up to you.

[Burkhard Hassel]

String >> StringBuffer > StringBuilder.

this

class Main {
public static void main(String[] args) {
final int max = 3000;
long time = System.currentTimeMillis();
String s = "";
for(int i=0; i<max; i++)
s+="concatenate";
time = System.currentTimeMillis() - time;
System.out.println("String: " + time + " ms");
System.out.println("to compare it with the others it should be 20* as long.");
System.out.println("so: String: " + (time*20) + " ms");
s=null;
System.gc();
StringBuffer sb = new StringBuffer();
time = System.currentTimeMillis();
for(int i=0; i<max*20; i++)
sb.append("concatenate");
time = System.currentTimeMillis() - time;
System.out.println("StringBuffer: " + time + " ms");
sb = null;
System.gc();
StringBuilder sd = new StringBuilder();
time = System.currentTimeMillis();
for(int i=0; i<max*20; i++)
sd.append("concatenate");
time = System.currentTimeMillis() - time;
System.out.println("StringBuilder: " + time + " ms");
}
}

produced
String: 1328 ms
to compare it with the others it should be 20* as long.
so: String: 26560 ms
StringBuffer: 78 ms
StringBuilder: 62 ms



Yours,
Bu.

[Scott Selikoff]

"nivya"

I'm afraid your name still does not conform to our naming policy. Please review the FAQ and update it appropriately.

Scott

[Raghavan Muthu]

This is a good link for this context.

http://www.precisejava.com/javaperf/j2se/StringAndStringBuffer.htm

Hope this will help