Java File lastModified() method with examples

1. Introduction

The lastModified() method returns the time of the last file modification.

2. Method signature

public long lastModified()

Parameters:

• method does not take any parameter

Returns

• long - a value representing the time the file was last modified, measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970), or 0L if the file does not exist or if an I/O error occurs

Throws

• SecurityException - when we do not have access to the file or directory

3. Examples

3.1. Prints the lastModified of a not existing file, a directory and existing file

package com.frontbackend.java.io;

import java.io.File;
import java.time.Instant;

public class FrontBackend {

    public static void main(String args[]) {

        try {
            File f1 = new File("/tmp/frontbackend.txt"); // does not exist
            File f2 = new File("/tmp");
            File f3 = new File("/tmp/exists.txt");

            System.out.printf("/tmp/frontbackend.txt - %s%n", f1.lastModified()); // 0 
            System.out.printf("/tmp - %s%n", f2.lastModified());
            System.out.printf("/tmp/exists.txt - %s%n", Instant.ofEpochMilli(f3.lastModified()));

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The output:

/tmp/frontbackend.txt - 0
/tmp - 1588103611000
/tmp/exists.txt - 2020-04-28T19:53:31Z

4. Conclusion

In this article, we presented a way to check the last modification date using Java IO API. The lastModified method returns time in milliseconds that could be easily converted to the Java 8 Instant object using Instant.ofEpochMilli method.