[!INDEX]

1. Buffer Constructor + SB() + SB("raj") + mt() capacity
2. lenght, charAt, delete, deleteCharAt
3. equals, indexOf, lastIndexOf, insert, replace, reverse
4. subSequence, substring, setCharAt, setLength, ensureCapacity, trimToSize

1. Buffer Constructor + SB() + SB("raj") + mt() capacity

package package2;
public class Main1 {
    public static void main(String[] args) {
        StringBuffer s1 = new StringBuffer(); /*Create-obj, store 16 characters*/
        System.out.println(s1.capacity());  //16
        StringBuffer s2 = new StringBuffer("Rajat");
        System.out.println(s2.capacity()); //default + 16
        StringBuffer s3 = new StringBuffer(1000);  
                System.out.println(s3.capacity()); //1000
                StringBuffer s4 = new StringBuffer("Rajat");
                s4.append("null");
                System.out.println(s4);
                System.out.println(s4.capacity());
            /* append = 16 char */
                StringBuffer s5 = new StringBuffer();        
                s5.append("12345_12345_1234");
                System.out.println("s5 : "+s5.capacity()); //34
            /* append = 17 char */
                StringBuffer s6 = new StringBuffer();        
                s6.append("12345_12345_12345");
                System.out.println("s6 : "+s6.capacity()); //34 = ((16*2)+2)
            /* append = 35 char,*/
        }
   }         

2. lenght, charAt, delete, deleteCharAt

package package2;
public class Main1 {
    public static void main(String[] args) {
        /* lenght m/T */
            StringBuffer sl1 = new StringBuffer("rajat");        
            System.out.println(sl1.length()); //5
        /* charAt m/T */
            StringBuffer sl2 = new StringBuffer("rajat");        
            System.out.println(sl2.charAt(3)); //a
        /* delete m/T */
            StringBuffer sd1 = new StringBuffer("rajat is my name");      
            System.out.println(sd1.delete(2, 4)); //rat is my name
        /* delete char at */    
            StringBuffer sd2 = new StringBuffer("rajat is my name");      
            System.out.println(sd2.deleteCharAt(3)); //rajt is my name

3. equals, indexOf, lastIndexOf, insert, replace, reverse

package package2;
public class Main1 {
    public static void main(String[] args) {
            /* equals */
            // StringBuffer class does not override equals method of Object class but
            // String class override the equals method of Object class    
            StringBuffer se1 = new StringBuffer("rajat is my name");
            StringBuffer se2 = new StringBuffer("rajat is my name");      
            System.out.println(se1.equals(se2)); // diff. obj , false
            StringBuffer se3 = se1.append("hi");
            System.out.println(se1.equals(se3)); // same obj., true
        /* indexOf + lastIndexOf */        
            StringBuffer si1 = new StringBuffer("rajat is my name");
            System.out.println(si1.indexOf("j")); //2
            System.out.println(si1.lastIndexOf("m")); //14
        /* insert */
            StringBuffer si2 = new StringBuffer("rajat is my name");
            System.out.println(si2.insert(3,"bok")); //rajbokat is my name
        /* replace */
            StringBuffer sr = new StringBuffer("rajat is my name");
            System.out.println(sr.replace(3,4,"X")); //rajXt is my name
        /* reverse */
            StringBuffer sr1 = new StringBuffer("rajat is my name"); 
            System.out.println(sr1.reverse())// eman ym si tajar
    }   
}   

4. subSequence, substring, setCharAt, setLength, ensureCapacity, trimToSize

package package2;
public class Main1 {
    public static void main(String[] args) {
         /* subSequence */
            StringBuffer ss1 = new StringBuffer("rajat is my name");    
            System.out.println(ss1.subSequence(3,5)); //at
         /*substring*/
            StringBuffer ss2 = new StringBuffer("rajat is my name");    
            System.out.println(ss2.substring(5)); // is my name
         /*substring */    
            StringBuffer ss3 = new StringBuffer("rajat is my name");        
            System.out.println(ss3.substring(3,6)); //at
            StringBuffer ss4 = new StringBuffer();
            System.out.println(ss4.capacity()); //16
            ss4.ensureCapacity(1000);//sop-ss4.capacity() : 1000            
         /* setCharAt */
            StringBuffer ss5 = new StringBuffer("this is java code");
            ss5.setCharAt(3,'A');
            System.out.println(ss5); //thiA is java code
         /* set lenght */    
            StringBuffer ss6 = new StringBuffer("this is java code");
            ss6.setLength(5); //fixed lenght of ss6
            System.out.println(ss6); //this
         /* ensure capacity */    
            StringBuffer ss7 = new StringBuffer();
            ss7.ensureCapacity(100);
         /* append */                    
            ss7.append("book"); //fixed lenght of ss6
            System.out.println(ss7.capacity()); //100
         /* trim to size */        
            ss7.trimToSize();
            System.out.println(ss7.capacity()); //  4  

    }
  }