How to Remove or Trim All White Spaces from a String in Java

In this short article, we look at how to remove or trim all white spaces from a given string in Java.

Let's first we'll write a Java method to trim all whitespace from the given String that is trim white spaces from leading, trailing, and in between characters.

trimAllWhitespace(String str) Method

Let's write a Java method with logic to remove all white spaces.

Logical steps

1. Iterate over each character of a given String.
2. Check each character with white space using the built-in Character.isWhitespace(c) method.
3. If the character is not a white space then append a character to the StringBuilder instance.
4. Finally, return String via calling the toString() method on the StringBuilder instance.

/**
 * Trim <i>all</i> whitespace from the given {@code String}:
 * leading, trailing, and in between characters.
 * @param str the {@code String} to check
 * @return the trimmed {@code String}
 * @see java.lang.Character#isWhitespace
 */
public static String trimAllWhitespace(String str) {
    if (!hasLength(str)) {
        return str;
    }

    int len = str.length();
    StringBuilder sb = new StringBuilder(str.length());
    for (int i = 0; i < len; i++) {
        char c = str.charAt(i);
        if (!Character.isWhitespace(c)) {
            sb.append(c);
        }
    }
    return sb.toString();
}

Complete Java Program

Here is a complete Java program to demonstrate the above method with the input value " Java Guides ".

package com.javaguides.corejava.string;

/**
 * @author Ramesh Fadatare
 *
 */
public class StringTrimAllWhitespace {


    public static void main(String[] args) {
        String str = "  Java    Guides    ";
        String result = trimAllWhitespace(str);
        System.out.println(result);
    }
    /**
     * Trim <i>all</i> whitespace from the given {@code String}:
     * leading, trailing, and in between characters.
     * @param str the {@code String} to check
     * @return the trimmed {@code String}
     * @see java.lang.Character#isWhitespace
     */
    public static String trimAllWhitespace(String str) {
        if (!hasLength(str)) {
            return str;
        }

        int len = str.length();
        StringBuilder sb = new StringBuilder(str.length());
        for (int i = 0; i < len; i++) {
            char c = str.charAt(i);
            if (!Character.isWhitespace(c)) {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    public static boolean hasLength(String str) {
        return (str != null && !str.isEmpty());
    }
}

Output:

JavaGuides

Related Java String Programs with Output

1. Java Program to Find the First Non-repeated Character in a String
2. Java Program to Check Palindrome String
3. Java Program to Find Duplicate Characters in a String
4. Java Program to Find Duplicate Words in a String
5. Java Program to Find All the Permutations of a String
6. Java Program to Count Occurrences of Words in a String
7. Java Program to Count the Occurrences of Each Character
8. Java Program to Count Vowels and Consonants in a String
9. Java program to Count the Number of Duplicate Words in a String
10. Java Program to Count Number of Words in Given String
11. Java Program to Count the Number of Occurrences of Substring in a String
12. Java Program to Count the Occurrences of Each Character in String
13. Java Program to Merge Two String Arrays
14. Java Program to Remove Duplicate Words from String
15. Java Program to Reverse a String(5 ways)
16. Java Program to Reverse Each Word of a String
17. Java Program to Swap Two Strings
18. How to Check if the String Contains Only Digits
19. How to Check if the String Contains Only Letters
20. How to Check If the String Contains Only Letters or Digits
21. Java Program to Swap Two Strings Without Using Third Variable