File renameTo(File) in Java

renameTo(File): This method is available in the java.io.File class of Java.

Syntax:

boolean java.io.File.renameTo(File dest)

This method takes one argument. This method renames the file denoted by this abstract pathname.

Parameters: One parameter is required for this method.

dest: The new abstract pathname for the named file.

Returns: true if and only if the renaming succeeded; false otherwise.

Throws:

1. SecurityException - If a security manager exists and its java.lang.SecurityManager.checkWrite(java.lang.String) method denies writing access to either the old or new pathnames

2. NullPointerException - If parameter dest is null

Approach 1: When no exception

Java

import java.io.File;

public class FilerenameTo {
    public static void main(String[] args) {

        String pathname = "D:\\hello.txt";
        File file = new File(pathname);

        File dest = new File(pathname);

        System.out.println(file.renameTo(dest));
    }
}

Output:

true

Approach 2: NullPointerException

Java

import java.io.File;

public class FilerenameTo {
    public static void main(String[] args) {

        String pathname = "D:\\hello.txt";
        File file = new File(pathname);

        File dest = null;

        System.out.println(file.renameTo(dest));
    }
}

Output

Exception in thread "main" java.lang.NullPointerException
	at java.base/java.io.File.renameTo(File.java:1401)