How to create a tar.gz file using Java

In order to compress files and folders as a tar.gz file in Java we can make use of the Apache Commons Compress dependency.

Maven Dependency:

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-compress</artifactId>
    <version>1.23.0</version>
</dependency>

Gradle Dependency:

implementation group: 'org.apache.commons', name: 'commons-compress', version: '1.23.0'

Code Example:

import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
import org.apache.commons.compress.compressors.gzip.GzipCompressorOutputStream;

import java.io.*;
import java.util.zip.Deflater;

public class TarGzCreatorWithJava {

    public static void main(String[] args) {
        
        String sourceDirPath = "/data";
        String tarGzFilePath = "/data/data.tar.gz";

        try {
            var fileOutputStream = new FileOutputStream(tarGzFilePath);
            var gzipCompressorOutputStream = new GzipCompressorOutputStream(fileOutputStream);
            var tarArchiveOutputStream = new TarArchiveOutputStream(gzipCompressorOutputStream);
            tarArchiveOutputStream.setBigNumberMode(TarArchiveOutputStream.BIGNUMBER_STAR);
            tarArchiveOutputStream.setLongFileMode(TarArchiveOutputStream.LONGFILE_GNU);

            File sourceDir = new File(sourceDirPath);
            addFilesToTar(sourceDir, tarOut, "");

            tarOut.finish();
            tarOut.close();

            System.out.println("File created.. : " + tarGzFilePath);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void addFilesToTar(File source, TarArchiveOutputStream tarOut, String parentDir) throws IOException {
        File[] files = source.listFiles();
        if (files != null) {
            for (File file : files) {
                if (file.isDirectory()) {
                    addFilesToTar(file, tarOut, parentDir + file.getName() + "/");
                } else {
                    TarArchiveEntry entry = new TarArchiveEntry(parentDir + file.getName());
                    entry.setSize(file.length());
                    tarOut.putArchiveEntry(entry);

                    try (FileInputStream fis = new FileInputStream(file)) {
                        byte[] buffer = new byte[1024];
                        int read;
                        while ((read = fis.read(buffer)) != -1) {
                            tarOut.write(buffer, 0, read);
                        }
                    }

                    tarOut.closeArchiveEntry();
                }
            }
        }
    }
}