The **`trim()` method** in Java eliminates leading and trailing whitespaces in a string. Here is how the method is defined:

```java
public String trim()
```
The method takes no parameters, returns a string, and can be called by any string. However, `trim()` will not alter the original string; a new trimmed string will be returned instead. 

Below ​is a copy of the original string with its whitespaces removed.

# Code

The following code snippet demonstrates the usage of the `trim()` method:

class Program {
    public static void main( String args[] ) {
      String str = "     the quick brown fox     ";
      System.out.println("String with whitespaces: " + str);
      String trimmedStr = str.trim();
      System.out.println("Trimmed string: " + trimmedStr);
    }
}

How to use Java's string trim() method

The trim() method in Java removes leading and trailing whitespaces from a string, returning a new string without altering the original.