import org.apache.commons.io.IOUtils;
import java.io.*;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

public class UnzipInJava
{
    public static void main(String[] args) throws IOException {

        String jarFile = "./src/main/my_Jars/myJar1.jar";
        String outputPath = "./out/test123/";

        unzipFile(jarFile, outputPath);
    }

    private static void unzipFile(String zipPath, String outputPath) throws IOException {
        ZipFile zipFile = new ZipFile(zipPath);
        try {
            Enumeration<? extends ZipEntry> entries = zipFile.entries();
            while (entries.hasMoreElements()) {
                ZipEntry entry = entries.nextElement();
                File entryDestination = new File(outputPath,  entry.getName());
                if (entry.isDirectory()) {
                    entryDestination.mkdirs();
                } else {
                    entryDestination.getParentFile().mkdirs();
                    InputStream in = zipFile.getInputStream(entry);
                    OutputStream out = new FileOutputStream(entryDestination);
                    IOUtils.copy(in, out);
                    IOUtils.closeQuietly(in);
                    out.close();
                }
            }
        } finally {
            zipFile.close();
        }
    }
}