How to Count Words in a String in Java

The Challenge

Count the number of words in a string - words are separated by spaces!

Solution

Method 1: Using split()

java

String text = "Java is fun to learn";
String[] words = text.split("\\s+");
int wordCount = words.length;

System.out.println("Word count: " + wordCount);
// Output: Word count: 5

Method 2: Using StringTokenizer

java

import java.util.StringTokenizer;

String text = "Java is fun to learn";
StringTokenizer tokenizer = new StringTokenizer(text);
int wordCount = tokenizer.countTokens();

System.out.println("Word count: " + wordCount);
// Output: Word count: 5

Method 3: Manual Counting

java

String text = "Java is fun to learn";
int wordCount = 0;
boolean isWord = false;

for (int i = 0; i < text.length(); i++) {
    if (Character.isWhitespace(text.charAt(i))) {
        isWord = false;
    } else if (!isWord) {
        wordCount++;
        isWord = true;
    }
}

System.out.println("Word count: " + wordCount);
// Output: Word count: 5

Did You Know?

The regex \\s+ matches one or more whitespace characters (spaces, tabs, newlines). This handles multiple spaces between words!

Watch Out!

Handle empty strings and leading/trailing spaces:

java

String text = "  Java  is  fun  ";
String[] words = text.trim().split("\\s+");
int wordCount = text.trim().isEmpty() ? 0 : words.length;

Real-World Use Cases

Text editors: Display word count
SEO tools: Analyze content length
Social media: Enforce character/word limits
Document analysis: Calculate reading time

›Short versionOpen if you only have a minute.

trim, then split on whitespace runs with \s+.
split(" ") treats each extra space as an empty word.
"".split("\\s+") returns a one-element array, so an all-space string counts as 1 unless you check empty first.
Punctuation stays attached to the token. This recipe does not know what a word is in every language.

Count words

Count whitespace-separated tokens, without counting empty tokens from repeated spaces.

Working approach

Trim the string.
If nothing remains, return 0.
Otherwise split on \\s+ and return the length.

Walk the sample

Input " Java is fun "
Trim leaves "Java is fun"
Split on whitespace runs yields three tokens
The count is 3

The trap

The empty string is the case the sample "Java is fun" never hits. After trim, split still reports one token.

java

static int wordCount(String text) {
    String trimmed = text.trim();
    if (trimmed.isEmpty()) {
        return 0;
    }
    return trimmed.split("\\s+").length;
}

What does " ".trim().split("\\s+").length return?

trim leaves the empty string. "".split("\\s+") returns an array of one empty string, so the length is 1.

Return 0 when the trimmed text is empty. split(" ") on "a b" has the other bug: it returns three tokens because the gap is an empty string.

Time O(n), space proportional to the number of tokens.

Easy to get wrong

Splitting on a single space and counting the empty strings between doubles.
Splitting before checking that trim left some text.