Program to demonstrate StringBuffer Methods

/* Program to demonstrate StringBuffer Methods */

class StringBufferDemo
{
    public static void main(String args[ ])
    {
        // using length() and capacity()
        StringBuffer sb= new StringBuffer("Java");
        System.out.println("\n StringBuffer : "+sb);

        System.out.println("\n********** length() and capacity() **************");
        System.out.println("\n Length : "+sb.length());
        System.out.println("\n Capacity : "+sb.capacity());

        // using ensureCapacity()
        System.out.println("\n\n********** ensureCapacity() **************");
        System.out.println("\n Allocating room for 50 extra characters");

        sb.ensureCapacity(50);
        System.out.println(" \n New Capacity after calling ensureCapacity(50) : "+sb.capacity());

        // using setLength()
        System.out.println("\n\n********** setLength() **************");
        System.out.println("When you increase the size of the buffer , null characters are added to the end of the existing buffer.");

        sb.setLength(2);
        System.out.println("\nNew Length after calling setLength(2) : "+sb.length());
        System.out.println("\n StringBUffer after setting new length : "+sb);

        // using charAt() and setCharAt()
        sb = new StringBuffer("Java");
        System.out.println("\n\n********** charAt() and setCharAt() **************");
        System.out.println("\nStringBuffer : "+sb);
        System.out.println("\ncharAt(0) before : "+sb.charAt(0));

        sb.setCharAt(0,'K');
        System.out.println("\nNew StringBuffer : "+sb);
        System.out.println("\ncharAt(0) after : "+sb.charAt(0));
       
        // using append()
        System.out.println("\n\n********** append() **************");
        StringBuffer sb1 = new StringBuffer(40);

        String s = sb1.append(" X = ").append(100).append(".").toString();
        System.out.println("\nAfter calling append(), String is : \n");
        System.out.println(s);

        // using insert()
        System.out.println("\n\n********** insert() **************");
        sb = new StringBuffer("Java is a true oriented Language");
        System.out.println("\nStringBuffer : "+sb);

        sb.insert(15, "object-");
        System.out.println("\n calling insert().....");
        System.out.println("\nAfter inserting 'object-' in StringBuffer, New String is :"+sb);

        // using reverse()
        System.out.println("\n\n********** reverse() **************");
        sb = new StringBuffer("JAVA");
        System.out.println("\nStringBuffer : "+sb);
        sb.reverse();
        System.out.println("\nAfter calling reverse() new StringBuffer : "+sb);

        // using delete() and deleteCharAt()
        System.out.println("\n\n********** delete() and deleteCharAt() **************");
        sb = new StringBuffer("Java is a true object-oriented Language");
        System.out.println("\nStringBuffer : "+sb);
        sb.delete(9,14);
        System.out.println("\n calling delete().....");
        System.out.println("\nAfter deleting 'true' from StringBuffer, New StringBuffer : \n"+sb);

        sb.deleteCharAt(0);
        System.out.println("\n calling deleteCharAt().....");
        System.out.println("\nAfter deleting first character, New StringBuffer: \n"+sb);

        // using replace()
        System.out.println("\n\n********** replace() **************");
        sb = new StringBuffer("He is Superstar.");
        System.out.println("\nStringBuffer : "+sb);

        sb.replace(3,5,"was");
        System.out.println("\ncalling replace()......");
         System.out.println("\nAfter replacing 'is' with 'was', New StringBuffer : "+sb);

        // using substring()
        System.out.println("\n\n********** substring() **************");
        sb = new StringBuffer("He is Superstar.");
        System.out.println("\nStringBuffer : "+sb);

        s = sb.substring(6,11);
        System.out.println("\n calling substring().....");       
        System.out.println("Retriving 'Super' from StringBuffer, New StringBuffer : "+s);       

    }
}