Zipping files

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

public class Main {
    public static final int BUFFER = 1024;
    public static void main(String[] args) throws IOException {
        String[] filesToZip = new String[] {"file.txt", "file2.txt"};

        byte tData[] = new byte[BUFFER];
        ZipOutputStream x = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream("myZip.zip"), BUFFER));

        for (int i = 0; i < filesToZip.length; i++) {
            BufferedInputStream y = new BufferedInputStream(new FileInputStream(filesToZip[i]), BUFFER);
            x.putNextEntry(new ZipEntry(filesToZip[i]));

            int counter;
            while ((counter = y.read(tData, 0, BUFFER)) != -1)
                x.write(tData, 0, counter);

            x.closeEntry();
            y.close();
        }
        x.close();
    }
}
                                    

Unzipping files

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

public class Main {
    public static final int BUFFER = 1024;
    public static void main(String[] args) throws IOException {
        ZipEntry z = null;
        byte tData[] = new byte[BUFFER];
        File catalogue = new File(System.getProperty("user.dir") + File.separator + "myZip"); // setting a path for the output directory

        if (!catalogue.exists()) // ensuring the output directory exists
            catalogue.mkdir();

        ZipInputStream x = new ZipInputStream(new BufferedInputStream(new FileInputStream("myZip.zip"), BUFFER));

        while ((z = x.getNextEntry()) != null) {
            BufferedOutputStream y = new BufferedOutputStream(new FileOutputStream(catalogue + File.separator + z.getName()), BUFFER);

            int counter;
            while ((counter = x.read(tData, 0, BUFFER)) != -1)
                y.write(tData, 0, counter);

            x.closeEntry();
            y.close();
        }
        x.close();
    }
}