Java - How to capitalize the first letter of each word in a String

In this section, we will show you four different ways to capitalize the first letter of each word in a String using Java.

Following ways can be used to capitalize the first letter of each word in a String in Java:

  1. By using Java 8 Stream
  2. By using StringTokenizer
  3. By using Pattern.compile() and replaceAll method
  4. By using Apache Commons Text

Example 1: Using Java 8 Stream

First split the string into an array using the split() method. Then array is passed to Arrays.stream() as a parameter that turns it into a Stream object. Then, we use the map() method from streams to capitalize each word and finally collect all words again and join them into one sentence.

import java.util.Arrays;
import java.util.stream.Collectors;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
      String str = "how are you";
      System.out.println("Input => " + str);
      String result = capitalize(str);
      System.out.println("Output => "+result);
    }

    public static String capitalize(String string) {

        if (string == null || string.isEmpty()) {
            return "Empty String";
        }

        return Arrays.stream(string.split("\\s+"))
                .map(str -> str.substring(0, 1).
                        toUpperCase() + str.substring(1))
                .collect(Collectors.joining(" "));
    }
}


Console Output:
Input => how are you
Output => How Are You


Assure that only the first character of a word is uppercase, and remaining characters of each word is lowercase:

import java.util.Arrays;
import java.util.stream.Collectors;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
      String str = "hoW are yOU";
      System.out.println("Input => " + str);
      String result = capitalizeFully(str);
      System.out.println("Output => "+result);
    }

    public static String capitalizeFully(String string) {

        if (string == null || string.isEmpty()) {
            return "Empty String";
        }

        return Arrays.stream(string.split("\\s+")).
                map(str -> str.substring(0, 1).toUpperCase() +
                        str.substring(1).toLowerCase()).
                collect(Collectors.joining(" "));
    }
}


Console Output:
Input => hoW are yOU
Output => How Are You


Example 2: Using StringTokenizer

StringTokenizer breaks the sentence into words. Then just iterate over each word and replace the first letter with an uppercase one.

import java.util.StringTokenizer;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
      String str = "how are you";
      System.out.println("Input => " + str);
      String result = capitalize(str);
      System.out.println("Output => "+result);

      System.out.println();

      String str1 = "java is very easy to learn";
      System.out.println("Input => " + str1);
      String result1 = capitalize(str1);
      System.out.println("Output => "+result1);
    }

    public static String capitalize(String string) {

        if (string == null || string.isEmpty()) {
            return "Empty String";
        }

        StringTokenizer tokens = new StringTokenizer(string);
        while (tokens.hasMoreElements()) {
            String token = (String) tokens.nextElement();
            string = string.replaceAll(token, token.
                    substring(0, 1).toUpperCase() +
                     token.substring(1));
        }
        return string;
    }
}


Console Output:
Input => how are you
Output => How Are You

Input => java is very easy to learn
Output => Java Is Very Easy To Learn


Assure that only the first character of a word is uppercase, and remaining characters of each word is lowercase:

import java.util.StringTokenizer;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
      String str = "hoW aRe yOU";
      System.out.println("Input => " + str);
      String result = capitalizeAll(str);
      System.out.println("Output => "+result);

      System.out.println();

      String str1 = "jaVa iS vERy eaSY tO leArn";
      System.out.println("Input => " + str1);
      String result1 = capitalizeAll(str1);
      System.out.println("Output => "+result1);
    }

    public static String capitalizeAll(String string) {

        if (string == null || string.isEmpty()) {
            return "Empty String";
        }

        StringTokenizer tokens = new StringTokenizer(string);
        while (tokens.hasMoreElements()) {
            String token = (String) tokens.nextElement();
            string = string.replaceAll(token, token.
                    substring(0, 1).toUpperCase() +
                     token.substring(1).toLowerCase());
        }
        return string;
    }
}


Console Output:
Input => hoW aRe yOU
Output => How Are You

Input => jaVa iS vERy eaSY tO leArn
Output => Java Is Very Easy To Learn


Example 3: Using Pattern.compile() and replaceAll method

If you are utilizing Java 9 or higher, it is possible to utilize a conventional expression with the String.replaceAll() method to capitalize the first letter of each word in a string. Pattern.compile() consumes a regular expression. The matcher() consumes the parameter that will be held against the Pattern. After that we supersede the first letter for each matching word again.

import java.util.regex.Pattern;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
        String str = "how are you";
        System.out.println("Input => " + str);
        String result = capitalize(str);
        System.out.println("Output => "+result);

        System.out.println();

        String str1 = "java is very easy to learn";
        System.out.println("Input => " + str1);
        String result1 = capitalize(str1);
        System.out.println("Output => "+result1);
    }

    public static String capitalize(String string) {

        if (string == null || string.isEmpty()) {
            return "Empty String";
        }

        return Pattern.compile("\\b(.)(.*?)\\b")
                .matcher(string)
                .replaceAll(match -> match.group(1).
                        toUpperCase() + match.group(2));
    }
}


Console Output:
Input => how are you
Output => How Are You

Input => java is very easy to learn
Output => Java Is Very Easy To Learn


Assure that only the first character of a word is uppercase, and remaining characters of each word is lowercase:

import java.util.regex.Pattern;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
        String str = "hoW aRe yOU";
        System.out.println("Input => " + str);
        String result = capitalizeAll(str);
        System.out.println("Output => "+result);

        System.out.println();

        String str1 = "jaVa iS vERy eaSY tO leArn";
        System.out.println("Input => " + str1);
        String result1 = capitalizeAll(str1);
        System.out.println("Output => "+result1);
    }

    public static String capitalizeAll(String string) {

        if (string == null || string.isEmpty()) {
            return "Empty String";
        }

        return Pattern.compile("\\b(.)(.*?)\\b")
                .matcher(string)
                .replaceAll(match -> match.group(1).
                        toUpperCase() + match.group(2).toLowerCase());
    }
}


Console Output:
Input => hoW aRe yOU
Output => How Are You

Input => jaVa iS vERy eaSY tO leArn
Output => Java Is Very Easy To Learn


Example 4: Using Apache Commons Text

Download Apache Commons Text

<dependency>
   <groupId>org.apache.commons</groupId>
   <artifactId>commons-text</artifactId>
   <version>1.10.0</version>
</dependency>

We can use the capitalize() method from the WordUtils class to capitalize each word in a string:

import org.apache.commons.text.WordUtils;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
        String str = "how are you";
        System.out.println("Input => " + str);
        String result = WordUtils.capitalize(str);
        System.out.println("Output => "+result);

        System.out.println();

        String str1 = "java is very easy to learn";
        System.out.println("Input => " + str1);
        String result1 = WordUtils.capitalize(str1);
        System.out.println("Output => "+result1);
    }
}

 

Console Output:
Input => how are you
Output => How Are You

Input => java is very easy to learn
Output => Java Is Very Easy To Learn


Assure that only the first character of a word is uppercase, and remaining characters of each word is lowercase:

The WordUtils class also provides the capitalizeFully() method that capitalizes the first character and turns the remaining characters of each word into lowercase:

import org.apache.commons.text.WordUtils;

public class Main {

    // Driver code
    public static void main(String[] args)
    {
        String str = "hoW aRe yOU";
        System.out.println("Input => " + str);
        String result = WordUtils.capitalizeFully(str);
        System.out.println("Output => "+result);

        System.out.println();

        String str1 = "jaVa iS vERy eaSY tO leArn";
        System.out.println("Input => " + str1);
        String result1 = WordUtils.capitalizeFully(str1);
        System.out.println("Output => "+result1);
    }
}


Console Output:
Input => hoW aRe yOU
Output => How Are You

Input => jaVa iS vERy eaSY tO leArn
Output => Java Is Very Easy To Learn

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