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Java Pattern pattern() Method

Last Updated : 11 Jul, 2025
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pattern() method of the Pattern class in Java is used to get the regular expression which is compiled to create this pattern. We use a regular expression to create the pattern and this method is used to get the same source expression. 

Example 1: Using the pattern() method to check the regex pattern passed for pattern matching.

Java 
// Java program to demonstrate
// Pattern.pattern() method
import java.util.regex.*;

public class Geeks 
{
    public static void main(String[] args)
    {
        // create a REGEX String
        String REGEX = "(.*)(for)(.*)?";

        // create the string in which you want
      	// to search
        String actualString = "code of Machine";

        // create pattern
        Pattern pattern1 = Pattern.compile(REGEX);

        // find the regular expression of pattern
        String RegularExpression = pattern1.pattern();

        System.out.println("Pattern's RegularExpression = "
                           + RegularExpression);
    }
}

Output
Pattern's RegularExpression = (.*)(for)(.*)?

Syntax

public String pattern()

  • Parameters: This method does not accepts anything as parameter. 
  • Return Value: This method returns the pattern's source regular expression.  

Example 2: Using the pattern() method in conjunction with a Matcher.

Java 
// Java program to demonstrate the usage of 
// regular expressions in pattern matching
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Geeks 
{  
    public static void main(String[] args)
    {
        // Input strings to match the regex against
        String input1 = "The quick brown fox jumps over the lazy dog";
        String input2 = "The quick red fox jumps over the lazy dog";
        
        // Regex pattern to match case-insensitive 'the'
        String regex = "(?i)the";
     	
        // Compile the regex pattern
        Pattern pattern = Pattern.compile(regex);
        
        // Create matchers for both input strings
        Matcher matcher1 = pattern.matcher(input1);
        Matcher matcher2 = pattern.matcher(input2);
        
        // Find and print all matches in input1
        while (matcher1.find()) {
            System.out.println("Match 1: " + matcher1.group());
        }
        
        // Find and print all matches in input2
        while (matcher2.find()) {
            System.out.println("Match 2: " + matcher2.group());
        }
    }
}

Output
Match 1: The
Match 1: the
Match 2: The
Match 2: the

A

AmanSingh2210
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