Think about how applications save game progress, logs, or user settings — all of this requires file access. File handling in Java allows programs to read from and write to files, which is fundamental for persistent data storage.
Understanding Java’s file handling mechanisms unlocks a wide range of possibilities in building data-driven and real-world applications that interact with external systems.
File Handling in Java enables applications to create, read, update, and delete files. It uses classes from the java.io and java.nio.file packages to perform operations.
File – Represents a file or directory.FileReader, BufferedReader – For reading from files.FileWriter, BufferedWriter, PrintWriter – For writing to files.Scanner – Used to read content from files line by line.Files – NIO.2 class for advanced file operations.Always close file streams using try-with-resources or manually to avoid memory leaks.
import java.io.FileWriter;
import java.io.IOException;
public class WriteFileExample {
public static void main(String[] args) {
try (FileWriter writer = new FileWriter("example.txt")) {
writer.write("Hello, File Handling in Java!");
System.out.println("File written successfully.");
} catch (IOException e) {
e.printStackTrace();
}
}
}
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class ReadFileExample {
public static void main(String[] args) {
try {
File file = new File("example.txt");
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
System.out.println(scanner.nextLine());
}
scanner.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
Storing and retrieving logs, configuration files, and data without using a database.
Processing files uploaded by users in desktop and web applications.
Storing temporary files or output files during compilation or execution.
FileWriter writes directly to a file, while BufferedWriter uses a buffer to improve writing performance by minimizing IO operations.
Use the try-with-resources statement which automatically closes the file streams, or manually call close() in a finally block.
The File class represents a file or directory path and provides methods to create, delete, or check file information (like existence, length, or type).