Capitalize First Character Of Each Word In A String In Java

This post will discuss how to capitalize the first character of each word in a given text in Java.

1. Naive solution

A naive solution is to split the given text using space as a delimiter. Then we iterate through the word array, capitalize the first character of each word, and append it to a StringBuilder along with space. Finally, return the string representation of the StringBuilder.

// Java program to capitalize the first character of each word in a string

class Main

{

public static String capitalize(String str)

{

String[] words = str.split("\\s");

StringBuilder sb = new StringBuilder();

for (String s: words)

{

if (!s.equals(""))

{

sb.append(Character.toUpperCase(s.charAt(0)));

sb.append(s.substring(1));

}

sb.append(" ");

}

// `trim()` to remove extra space at the end before returning

return sb.toString().trim();

}

public static void main(String[] args)

{

String sentence = "techie delight is awesome!";

String str = capitalize(sentence);

System.out.println(str);

}

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Output:

Techie Delight Is Awesome!

2. Using `WordUtils` from Apache Commons

The simplest solution is to use the WordUtils class from Apache Commons Lang. It already provides a capitalize() method that serves the same purpose.

import org.apache.commons.lang3.text.WordUtils;

class Main

{

public static void main(String[] args)

{

String sentence = "techie delight is awesome!";

String str = WordUtils.capitalize(sentence);

System.out.println(str);

}

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Output:

Techie Delight Is Awesome!

3. Using Java 8

In Java 8, we can get the stream of the words in the given text, capitalize the first character of each word, and collect it using Collectors.

⮚ Using Pattern.splitAsStream() to get Stream

import java.util.regex.Pattern;

import java.util.stream.Collectors;

class Main

{

public static String capitalize(String s)

{

if (s.equals("")) {

return s;

}

return s.substring(0, 1).toUpperCase() + s.substring(1);

}

public static void main(String[] args)

{

String sentence = "techie delight is awesome!";

String str = Pattern.compile("\\s")

.splitAsStream(sentence)

.map(Main::capitalize)

.collect(Collectors.joining(" "));

System.out.println(str);

}

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Output:

Techie Delight Is Awesome!

⮚ Using Stream.of() to get Stream

import java.util.stream.Collectors;

import java.util.stream.Stream;

class Main

{

public static String capitalize(String s)

{

if (s.equals("")) {

return s;

}

return s.substring(0, 1).toUpperCase() + s.substring(1);

}

public static void main(String[] args)

{

String sentence = "techie delight is awesome!";

String str = Stream.of(sentence.split("\\s"))

.map(Main::capitalize)

.collect(Collectors.joining(" "));

System.out.println(str);

}

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Output:

Techie Delight Is Awesome!

This is equivalent to:

import java.util.StringJoiner;

class Main

{

public static String capitalize(String s)

{

if (s.equals("")) {

return s;

}

return s.substring(0, 1).toUpperCase() + s.substring(1);

}

public static void main(String[] args)

{

String sentence = "techie delight is awesome!";

StringJoiner joiner = new StringJoiner(" ");

for (String s : sentence.split("\\s")) {

joiner.add(capitalize(s));

}

String str = joiner.toString();

System.out.println(str);

}

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Output:

Techie Delight Is Awesome!

4. Using Guava Library

We can also use the Joiner class from Guava, along with Splitter and Iterables class, as demonstrated below:

import com.google.common.base.Joiner;

import com.google.common.base.Splitter;

import com.google.common.collect.Iterables;

import org.apache.commons.lang3.StringUtils;

class Main

{

public static String capitalize(String s)

{

if (s.equals("")) {

return s;

}

return s.substring(0, 1).toUpperCase() + s.substring(1);

}

public static void main(String[] args)

{

String sentence = "techie delight is awesome!";

String str = Joiner.on(' ')

.join(Iterables.transform(Splitter.on(' ').split(sentence), Main::capitalize));

System.out.println(str);

}

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Output:

Techie Delight Is Awesome!

5. Using Regex

We can also take the help of regular expressions in Java to capitalize the first character of each word, as shown below:

import java.util.regex.Matcher;

import java.util.regex.Pattern;

class Main

{

public static String capitalize(String str)

{

StringBuffer sb = new StringBuffer();

Matcher matcher = Pattern.compile("\\b(\\w){1}").matcher(str);

while (matcher.find()) {

matcher.appendReplacement(sb, matcher.group(1).toUpperCase());

}

matcher.appendTail(sb);

return sb.toString();

}

public static void main(String[] args)

{

String sentence = "techie delight is awesome!";

String str = capitalize(sentence);

System.out.println(str);

}

Download Run Code

Output:

Techie Delight Is Awesome!

That’s all about capitalizing the first character of each word in a Java String.

Capitalize First Character Of Each Word In A String In Java

1. Naive solution

2. Using WordUtils from Apache Commons

3. Using Java 8

4. Using Guava Library

5. Using Regex

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2. Using `WordUtils` from Apache Commons