Java regex program to match parenthesis "(" or, ")".

Following regular expression accepts a string with parenthesis −

"^.*[\(\)].*$";

• ^ matches the starting of the sentence.

• .* Matches zero or more (any) characters.

• [\(\)] matching parenthesis.

• $ indicates the end of the sentence.

Example 1

 Live Demo

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class SampleTest {
   public static void main( String args[] ) {
      String regex = "^.*[\(\)].*$";
      //Reading input from user
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter data: ");
      String input = sc.nextLine();
      //Instantiating the Pattern class
      Pattern pattern = Pattern.compile(regex);
      //Instantiating the Matcher class
      Matcher matcher = pattern.matcher(input);
      //verifying whether a match occurred
      if(matcher.find()) {
         System.out.println("Input accepted");
      }else {
         System.out.println("Not accepted");
      }
   }
}

Output 1

Enter data:
sample(text) with parenthesis
Input accepted

Output 2

Enter data:
sample text
Not accepted

Example 2

 Live Demo

import java.util.Scanner;
public class Example {
   public static void main(String args[]) {
      //Reading String from user
      System.out.println("Enter email address: ");
      Scanner sc = new Scanner(System.in);
      String e_mail = sc.nextLine();
      //Regular expression
      String regex = "^.*[\(\)].*$";
      boolean result = e_mail.matches(regex);
      if(result) {
         System.out.println("Valid match");
      } else {
         System.out.println("Invalid match");
      }
   }
}

Output 1

Enter email address:
sample(text) with parenthesis
Valid match

Output 2

Enter email address:
sample text
Invalid match