append() in Java

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The append() method concatenates the string representation of any other type of data to the end of the invoking StringBuffer object. It has overloaded versions for all the built-in types and for Object. Here are a few of its forms: StringBuffer append(String str)
StringBuffer append(int num)
StringBuffer append(Object obj)

String.valueOf( ) is called for each parameter to obtain its string representation. The result is appended to the current StringBuffer object. The buffer itself is returned by each version of append(). This allows subsequent calls to be chained together, as shown in the following example:

// Demonstrate append().
class appendDemo {
public static void main(String args[]) {
String s;
int a = 42;
StringBuffer sb = new StringBuffer(40);
s = sb.append("a = ").append(a).append("!").toString();
System.out.println(s);
}
}

The output of this example is shown here:

a = 42!

The append( ) method is most often called when the + operator is used on String objects. Java automatically changes modifications to a String instance into similar operations on a StringBuffer instance. Thus, a concatenation invokes append( ) on a StringBuffer object. After the concatenation has been performed, the compiler inserts a call to toString( ) to turn the modifiable StringBufferback into a constant String. All of this may seem unreasonably complicated. Why not just have one string class and have it behave more or less like StringBuffer? The answer is performance. There are many optimizations that the Java run time can make knowing that Stringobjects are immutable. Thankfully, Java hides most of the complexity of conversion between Strings
and StringBuffers. Actually, many programmers will never feel the need to use StringBuffer directly and will be able to express most operations in terms of the + operator on String variables.


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Comments(12)


1. View Comment

Its really good.....

View Tutorial          By: Shivam at 2009-04-02 03:58:51
2. View Comment

good one

View Tutorial          By: vij at 2009-06-03 16:00:12
3. View Comment

One of the best

View Tutorial          By: Sudhir at 2009-12-22 01:45:28
4. View Comment

Good one. Clear basic concept

View Tutorial          By: Joshua at 2010-03-12 01:13:08
5. View Comment

good example

View Tutorial          By: WANT TO KNOW WHY WE USE APPEND at 2011-06-14 00:39:48
6. View Comment

Excellent. I want you to publish about memory allocation for every sample programs side by side, as it plays a major role in live projects. For example :

public class stringmemory
{
public static void main(String[] args){
String str = "Sri seshaa";
String str1 = " Sri seshaa";
String str2 = str + str1 + " technologies";

StringBuffer s;
String d;
StringBuffer bufr = new StringBuffer(str);
s = bufr.append(str2);
d = String.valueOf(str);
System.out.println("......");
System.out.println(str2);
System.out.println("......");
System.out.println(d);
}
}

In this the memory allocated for concatenation in string class is more compared to the append operation in StringBuffer. Like this there are many advantages and disadvantages in it. Please publish it also, it will be helpful for the young programmers like me.


View Tutorial          By: Mohamed firnaz at 2011-12-07 04:54:27
7. View Comment

thank you for your excellent explaination..! :)

View Tutorial          By: marios at 2012-05-16 16:17:31
8. View Comment

Best Explanation & gud example by finnaz.........!
By: Umair Shuja at Iqra University on 2012-11-28


View Tutorial          By: Umair Shuja at 2012-11-28 10:53:35
9. View Comment

Good Example esp. way it was presented.

View Tutorial          By: Arunlal at 2013-06-20 11:56:43
10. View Comment

Sencillo y directo. No se podía explicar mejor.

View Tutorial          By: Eligio at 2013-09-03 05:26:35
11. View Comment

Cant undrstand clearly

View Tutorial          By: rathika at 2014-06-09 11:02:16
12. View Comment

it was nice and helpful for me.

View Tutorial          By: mayank at 2015-03-01 08:35:48

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