Open Zip and Save Password Protected

Open a .zip (non-encrypted) and then save it password-protected.

Download Chilkat Java Library

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    CkZip zip = new CkZip();

    boolean success;

    //  Any string unlocks the component for the 1st 30-days.
    success = zip.UnlockComponent("Anything for 30-day trial");
    if (success != true) {
        System.out.println(zip.lastErrorText());
        return;
    }

    success = zip.OpenZip("test.zip");
    if (success != true) {
        System.out.println(zip.lastErrorText());
        return;
    }

    //  Set a password and indicate that password protection
    //  should be used when writing the .zip
    zip.put_EncryptPassword("secret");
    zip.put_PasswordProtect(true);

    //  Write the zip (overwrites test.zip)

    success = zip.WriteZipAndClose();
    if (success != true) {
        System.out.println(zip.lastErrorText());
        return;
    }

    System.out.println("Zip Re-Written with Password Protection!");
  }
}