StringBuffer methods insert, delete and deleteCharAt : StringBuffer StringBuilder « Development « Java Tutorial

public class MainClass {
  public static void main(String args[]) {
    Object objectRef = "hello";
    String string = "goodbye";
    char charArray[] = { 'a', 'b', 'c', 'd', 'e', 'f' };
    boolean booleanValue = true;
    char characterValue = 'K';
    int integerValue = 7;
    long longValue = 10000000;
    float floatValue = 2.5f;
    double doubleValue = 33.3;

    StringBuffer buffer = new StringBuffer();

    buffer.insert(0, objectRef);
    buffer.insert(0, "  ");
    buffer.insert(0, string);
    buffer.insert(0, "  ");
    buffer.insert(0, charArray);
    buffer.insert(0, "  ");
    buffer.insert(0, charArray, 3, 3);
    buffer.insert(0, "  ");
    buffer.insert(0, booleanValue);
    buffer.insert(0, "  ");
    buffer.insert(0, characterValue);
    buffer.insert(0, "  ");
    buffer.insert(0, integerValue);
    buffer.insert(0, "  ");
    buffer.insert(0, longValue);
    buffer.insert(0, "  ");
    buffer.insert(0, floatValue);
    buffer.insert(0, "  ");
    buffer.insert(0, doubleValue);

    System.out.printf("buffer after inserts:\n%s\n\n", buffer.toString());

    buffer.delete(2, 6);

    System.out.printf("buffer after deletes:\n%s\n", buffer.toString());
buffer after inserts:
33.3  2.5  10000000  7  K  true  def  abcdef  goodbye  hello

buffer after deletes:
332.5 10000000  7  K  true  def  abcdef  goodbye  hello

6.15.StringBuffer StringBuilder
6.15.1.StringBuffer and StringBuilder
6.15.2.You can also create a StringBuffer object using a reference stored in a variable of type String:
6.15.3.Creating a String Object From a StringBuffer Object
6.15.4.Creating a StringBuffer object with a specific value for the capacity
6.15.5.Check the capacity of StringBuilder object
6.15.6.Adding String to a StringBuffer Object
6.15.7.The append() method returns a reference to the extended StringBuffer object
6.15.8.Calling append() method to construct a StringBuffer object
6.15.9.Appending a Substring: append part of the aString object to the buf object
6.15.10.Appending Basic Types: long, double
6.15.11.Appending a subset of the elements from a char array
6.15.12.StringBuffer methods charAt, setCharAt, getChars and reverse
6.15.13.StringBuffer methods insert, delete and deleteCharAt
6.15.14.Convert digit to character with Character.forDigit
6.15.15.Inserting Strings
6.15.16.The Length of a StringBuffer Object
6.15.17.Changing the StringBufer Length for a StringBuffer Object
6.15.18.To find out a StringBuffer object's capacity
6.15.19.The ensureCapacity() method changes the default capacity of a StringBuffer object
6.15.20.Finding the Position of a Substring
6.15.21.Specifying the index position in the buffer where the search is to start
6.15.22.Replacing a Substring in the Buffer
6.15.23.Extracting Characters From a Mutable String: charAt() and getChars() methods
6.15.24.Changing a single character in a StringBuffer object
6.15.25.Using the deleteCharAt() method to remove a character from a StringBuffer object at the index position
6.15.26.Removing several characters from a StringBuffer object
6.15.27.Remove substring from StringBuilder
6.15.28.Deletes text from the StringBuilder object
6.15.29.Reversing the sequence of characters in a StringBuffer object with the reverse() method