insert (int offset, char c)

public synchronized StringBuffer insert(int offset, char c)

Inserts the string representation of the char argument into this sequence at the indicated offset.

public class StringBufferInsert {
    public static void main(String args[]){
        StringBuffer str = new StringBuffer("String str is ");
        str.insert(str.length(), 'a');
        System.out.println(str);
    }
}

Output

String str is a

Prevoius                                                 Next                                                 Home