Home » Java programming language

Java StringBuilder replace() method with example

StringBuilder Class replace() method: Here, we are going to learn about the replace() method of StringBuilder Class with its syntax and example.
Submitted by Preeti Jain, on December 22, 2019

StringBuilder Class replace() method

• replace() method is available in java.lang package.
• replace() method is used to replaces the set of character lies b/w beg and end parameter with the characters in the given string.
• replace() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• replace() method may throw an exception at the time of replacing a set of characters with the given string.
  StringIndexOutOfBoundsException – This exception may throw when the first parameter beg < 0 , greater than length() or beg > end.

Syntax:

    public StringBuilder replace(int beg, int end, String s);

Parameter(s):

• int beg – represents the starting index to replace the set of character.
• int end – represents the ending index till replace the set of characters.
• String s – represents the string that will replace contents b/w beg and end.

Return value:

The return type of this method is StringBuilder, it returns this StringBuilder object.

Example:

// Java program to demonstrate the example 
// of replace (int beg , int end , String s)
// method of StringBuilder 

public class Replace {
    public static void main(String[] args) {
        int beg = 5;
        int end = 10;

        String s = "Program";
        // Creating an StringBuilder object
        StringBuilder st_b = new StringBuilder("Java World ");

        // Display st_b 
        System.out.println("st_b = " + st_b);


        // By using replace(beg,end,s) method is to replace the string 
        // from index "beg" to index "end" in st_b with the given string 
        //  ("Program")
        st_b.replace(beg, end, s);

        // Display st_b
        System.out.println("st_b.replace(beg,end,s) = " + st_b);
    }
}

Output

st_b = Java World 
st_b.replace(beg,end,s) = Java Program