checking long running task and timing out using java thread

public boolean checkInBackground() throws InterruptedException {
  final StringBuffer st = new StringBuffer();
  Thread thread = new Thread() {
   public void run() {
    try {
     check();
     st.append("done");
    } catch (Exception e) {
     e.printStackTrace();
    }
   }

   public void check() {
    //long running task
    while(true) {}
   };
  };
  thread.setDaemon(true);
  thread.start();
  thread.join(2 * 1000);
  if (st.toString().equals("done")) {
   return true;
  }
  return false;
 }

check long running task status using callable, future, ExecutorService in java

public boolean checkInBackground() {
  ExecutorService pool = Executors.newFixedThreadPool(1);
  Callable callable = new Callable() {
   @Override
   public Boolean call() throws Exception {
    check();
    return Boolean.TRUE;
   }
  };
  final Future future = pool.submit(callable);
  pool.shutdown();
  Boolean bool = Boolean.FALSE;
  try {
   bool = future.get(1, TimeUnit.SECONDS);
  } catch (Exception e) {
   future.cancel(true);
   bool = Boolean.FALSE;
  }
  return bool;
 }
public boolean check() {
//long running task
return false;
}

eclipselink refresh cache

If JPA 2.0 is used, this can be done using the JPA Cache interface:

em.getEntityManagerFactory().getCache().evictAll();

In JPA 1.0 this can be done using the EclipseLink IdentityMapAccessor:

((JpaEntityManager)em.getDelegate()).getServerSession().getIdentityMapAccessor().invalidateAll();

Source: http://wiki.eclipse.org/EclipseLink/Examples/JPA/Caching

Encrypt Decrypt in java

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class EncryptDecrypt {
 String passPhrase = "";

 public EncryptDecrypt() {
 }

 public EncryptDecrypt(String passPhrase) {
  super();
  this.passPhrase = passPhrase;
 }

 public String decrypt(String encrypted) throws Exception {
  DESKeySpec desKeySpec = new DESKeySpec(passPhrase.getBytes("UTF8"));
  SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("DES");
  SecretKey secretKey = secretKeyFactory.generateSecret(desKeySpec);
  BASE64Decoder base64decoder = new BASE64Decoder();
  byte[] encrypedBytes = base64decoder.decodeBuffer(encrypted);
  Cipher cipher = Cipher.getInstance("DES");
  cipher.init(Cipher.DECRYPT_MODE, secretKey);
  byte[] decryptedBytes = (cipher.doFinal(encrypedBytes));
  String decrypted = new String(decryptedBytes);
  return decrypted;
 }

 public String encrypt(String encrypt) throws Exception {
  DESKeySpec desKeySpec = new DESKeySpec(passPhrase.getBytes("UTF8"));
  SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("DES");
  SecretKey secretKey = secretKeyFactory.generateSecret(desKeySpec);
  BASE64Encoder base64encoder = new BASE64Encoder();
  byte[] bytes = encrypt.getBytes("UTF8");
  Cipher cipher = Cipher.getInstance("DES");
  cipher.init(Cipher.ENCRYPT_MODE, secretKey);
  String encryped = base64encoder.encode(cipher.doFinal(bytes));
  return encryped;
 }

 public String getPassPhrase() {
  return passPhrase;
 }

 public void setPassPhrase(String passPhrase) {
  this.passPhrase = passPhrase;
 }
}