insert( )

The

insert( )

method inserts one string into another. It is overloaded to accept values of all the simple types, plus

String

s,

Object

s, and

CharSequence

s. Like

append( )

, it calls

String.valueOf( )

to obtain the string representation of the value it is called with. This string is then inserted into the invoking

StringBuffer

object. These are a few of its forms:

StringBuffer insert(int index , String str )

StringBuffer insert(int index , char ch )

StringBuffer insert(int index , Object obj )

Here, index specifies the index at which point the string will be inserted into the invoking

StringBuffer

object.

The following sample program inserts “like” between “I” and “Java”:

append( )

The

append()

method concatenates the string representation of any other type of data to the end of the invoking

StringBuffer

object. It has several overloaded versions. 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( )

.

replace( )

You can replace one set of characters with another set inside a

StringBuffer

object by calling

replace()

. Its signature is shown here:

StringBuffer replace(int startIndex , int endIndex , String str ) The substring being replaced is specified by the indexes startIndex and endIndex. Thus, the substring at startIndex through endIndex –1 is replaced. The replacement string is passed in str.

The resulting

StringBuffer

object is returned.

The following program demonstrates

replace( )

:

substring( )

You can obtain a portion of a

StringBuffer

by calling

substring( )

. It has the following two forms:

String substring(int startIndex )

String substring(int startIndex , int endIndex )

The first form returns the substring that starts at startIndex and runs to the end of the invoking

StringBuffer

object. The second form returns the substring that starts at startIndex and runs through endIndex

BASIS FOR COMPARISON	STRING	STRINGBUFFER
Basic	The length of the String object is fixed.	The length of the StringBuffer can be increased.
Modification	String object is immutable.	StringBuffer object is mutable.
Performance	It is slower during concatenation.	It is faster during concatenation.
Memory	Consumes more memory.	Consumes less memory.
Storage	String constant pool.	Heap Memory.

StringBuffer Constructors

StringBuffer( ):

It reserves room for 16 characters without reallocation.

StringBuffer s=

new

StringBuffer();

StringBuffer( int size)

It accepts an integer argument that explicitly sets the size of the buffer.

StringBuffer s=

new

StringBuffer(20);

StringBuffer(String str):

It accepts a

String

argument that sets the initial contents of the StringBuffer object and reserves room for 16 more characters without reallocation.

StringBuffer s=

new

StringBuffer("FutureVisionBIE");