Chapter 12: StringBuffer

Introduction to Java StringBuffer class.

Section 12.1: String Buffer class

Key Points:

• used to created mutable (modifiable) string.

• Mutable: Which can be changed.

• is thread-safe i.e. multiple threads cannot access it simultaneously.

Methods:

• public synchronized StringBuffer append(String s)

• public synchronized StringBuffer insert(int offset, String s)

• public synchronized StringBuffer replace(int startIndex, int endIndex, String str)
• public synchronized StringBuffer delete(int startIndex, int endIndex)

• public synchronized StringBuffer reverse() public int capacity()

• public void ensureCapacity(int minimumCapacity) public char charAt(int index)

• public int length()

• public String substring(int beginIndex)

• public String substring(int beginIndex, int endIndex)

Example Showing difference between String and String Buffer implementation:

public static void main(String args[])

{

String str = “study”;

str.concat(“tonight”);

System.out.println(str);                       //  Output:  study

StringBuffer strB = new StringBuffer(“study”);

strB.append(“tonight”);

System.out.println(strB);                  //  Output:  studytonight

}

} class Test {