Java String trim() method
Syntax and Examples

Introduction

Sometimes your strings have leading or trailing whitespace – spaces, tabs, newlines – that you don't want. The `trim()` method provides a simple way to remove this unwanted whitespace from the beginning and end of a string without affecting the characters in between.

Syntax

public String trim()

Parameters

Parameter	Description
None	This method does not take any parameters.

Return Value

The trim() method returns a new string with leading and trailing whitespace removed.

Examples

Example 1: Basic Trimming

This example shows how to trim a simple string containing spaces at the beginning and end.

public class TrimExample {
  public static void main(String[] args) { 
    String str = "   Hello, World!   ";
    String trimmedStr = str.trim();
    System.out.println("Original String: \"" + str + "\"");
    System.out.println("Trimmed String: \"" + trimmedStr + "\"");
  }
}

Original String:   Hello, World!   
Trimmed String: Hello, World!

In this example, the leading and trailing spaces are removed from str before assigning it to trimmedStr. The original string remains unchanged.

Example 2: Trimming with Tabs and Newlines

This demonstrates how `trim()` handles tabs and newlines, not just spaces.

public class TrimExample2 {
  public static void main(String[] args) { 
    String str = "\t\n Hello World \n\t";
    String trimmedStr = str.trim();
    System.out.println("Original String: \"" + str + "\"");
    System.out.println("Trimmed String: \"" + trimmedStr + "\"");
  }
}

Original String: 	
 Hello World 
	
Trimmed String: Hello World 

Notice how the tabs and newlines at both ends of the string are removed. The content between these characters remains unaffected.

Example 3: Trimming an Empty String

This example illustrates what happens when you try to trim an empty string or a string containing only whitespace.

public class TrimExample3 {
  public static void main(String[] args) { 
    String str1 = "";
    String str2 = "   \t\n\t  ";
    String trimmedStr1 = str1.trim();
    String trimmedStr2 = str2.trim();
    System.out.println("Original String 1: \"" + str1 + "\"");
    System.out.println("Trimmed String 1: \"" + trimmedStr1 + "\"");
    System.out.println("Original String 2: \"" + str2 + "\"");
    System.out.println("Trimmed String 2: \"" + trimmedStr2 + "\"");
  }
}

Original String 1: 
Trimmed String 1: 
Original String 2:      	  
Trimmed String 2: 

When trimming an empty string, you get an empty string back. When trimming a string containing only whitespace, the result is also an empty string.

Example 4: Using Trim with User Input

This example shows how to use `trim()` when getting input from a user, which often contains leading or trailing spaces.

import java.util.Scanner;

public class TrimExample4 {
  public static void main(String[] args) { 
    Scanner scanner = new Scanner(System.in);
    System.out.print("Enter your name: ");
    String name = scanner.nextLine();
    String trimmedName = name.trim();
    System.out.println("Hello, " + trimmedName + "!");
    scanner.close();
  }
}

This code prompts the user for their name and then trims any leading or trailing spaces before displaying a greeting. This ensures that the displayed name is clean and professional.