Java-tutorial-Files-created-and-lastModified-and-Size-of-file-method-in-java-with-examples
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Explore Java file handling methods
Updated: 13/Feb/2025 by Computer Hope
File handling is a crucial concept in Java programming. Understanding how to retrieve file details such as creation time, last modified time, and file size helps developers manage and monitor files efficiently. This guide explains these file properties with practical Java examples.
Java provides the java.io.File
class, which includes methods to check whether a file exists, get its size, and retrieve its last modification date.
Before performing operations on a file, it’s essential to check if it exists using the exists()
method.
import java.io.File;
public class FileExistExample {
public static void main(String[] args) {
File myFile = new File("D:/Assignments/message.txt");
if (myFile.exists()) {
System.out.println("File exists: " + myFile.getName());
} else {
System.out.println("File does not exist.");
}
}
}
File exists: message.txt
The length()
method returns the file size in bytes.
import java.io.File;
public class FileSizeExample {
public static void main(String[] args) {
File myFile = new File("D:/Assignments/message.txt");
if (myFile.exists()) {
System.out.println("Size of file is: " + myFile.length() + " bytes");
} else {
System.out.println("File does not exist.");
}
}
}
Size of file is: 1024 bytes
The lastModified()
method returns the last modification time of a file in milliseconds since the epoch (January 1, 1970, UTC). We can format this using Date
class.
import java.io.File;
import java.util.Date;
public class FileLastModifiedExample {
public static void main(String[] args) {
File myFile = new File("D:/Assignments/message.txt");
if (myFile.exists()) {
System.out.println("File was modified on: " + myFile.lastModified());
Date lastModified = new Date(myFile.lastModified());
System.out.println("Formatted date: " + lastModified);
} else {
System.out.println("File does not exist.");
}
}
}
File was modified on: 1678923456789
Formatted date: Fri Mar 10 14:10:56 UTC 2025
Java’s File
class provides essential methods to check file existence, retrieve file size, and get the last modified date. Understanding these methods enhances file handling operations in Java applications. By using best practices, developers can efficiently manage file metadata for better performance and security.