Java: Replace each substring of a given string that matches the given regular expression with the given replacement

Last update on March 17 2025 13:24:18 (UTC/GMT +8 hours)

Write a Java program to replace each substring of a given string that matches the given regular expression with the given replacement.

Sample string: "The quick brown fox jumps over the lazy dog."

In the above string replace all the fox with cat.

Visual Presentation:

Sample Solution:

Java Code:

// Define a public class named Exercise25.
public class Exercise25 {
    
    // Define the main method.
    public static void main(String[] args) {
        // Declare and initialize a string variable.
        String str = "The quick brown fox jumps over the lazy dog.";

        // Replace all occurrences of 'fox' with 'cat'.
        String new_str = str.replaceAll("fox", "cat");
       
        // Display the original and modified strings for comparison.
        System.out.println("Original string: " + str);
        System.out.println("New String: " + new_str);
    }
}

Sample Output:

Original string: The quick brown fox jumps over the lazy dog.                                                 
New String: The quick brown cat jumps over the lazy dog.         

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to replace substrings matching a regular expression with a specified replacement text.
• Write a Java program to remove all non-alphanumeric characters from a string using regex replacement.
• Write a Java program to substitute multiple whitespace characters with a single space using regular expressions.
• Write a Java program to find and replace all occurrences of a pattern in a string while ignoring case.

Java Code Editor:

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