Hi,

Here is simple example for Base64 encoding a file:

package my.code;

import java.util.Base64;
import java.io.File;
import java.nio.file.Files;

public class Base64EncodeFile {

    public static void main(String[] args) {
        File file = new File("data.txt");
        try {
            byte[] fileContent = Files.readAllBytes(file.toPath());
            String encodedString = Base64.getEncoder().encodeToString(fileContent);
            System.out.println("Encoded:");
            System.out.println(encodedString);

            System.out.println("Decoded Data:");
            String decodedString = new String(Base64.getDecoder().decode(encodedString.getBytes()));
            System.out.println(decodedString);

        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }

}

Thanks