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Java programming Exercises: Check whether a string contains only a certain set of characters (a-z, A-Z and 0-9)

Java Regular Expression: Exercise-1 with Solution

Write a Java program to check whether a string contains only a certain set of characters (in this case a-z, A-Z and 0-9).

Sample Solution:

Java Code:

import java.util.Scanner;
public class test {
 
   public static void main(String[] args) {
	   
	    System.out.println(validate("ABCDEFabcdef123450"));
		System.out.println(validate("SQL"));		
		System.out.println(validate("Java"));
		System.out.println(validate("*&%@#!}{"));
		System.out.println(validate("w3resource.com"));
        }

   public static boolean validate(String text) {
    return text.matches("^[\\w]+$");
  }
}

Sample Output:

true
true
true
false
false    

Pictorial Presentation:

Java Regular Expression: Check whether a string contains only a certain set of characters (a-z, A-Z and 0-9).
Java Regular Expression: Check whether a string contains only a certain set of characters (a-z, A-Z and 0-9).

Flowchart :

Flowchart: Check whether a string contains only a certain set of characters (a-z, A-Z and 0-9).

Java Code Editor:

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Java: Tips of the Day

Split Java String by New Line

String lines[] = string.split("\\r?\\n");

There's only really two newlines (UNIX and Windows) that you need to worry about.

Ref: https://bit.ly/3dHk7ip