tm.begin();
  em.persist(new Fruit("apple", 1));
  tm.commit();

  tm.begin();
  Fruit.enableSimulationFlag();
  try {
     Fruit fruit = em.find(Fruit.class, 1);
     assertNull(fruit);
 } catch(PersistenceException failed) {
   fail("EntityManager.find() should return null but instead threw an exception", failed);
 } finally {
  Fruit.clearSimulationFlag(): 
 }
}

@Entity
public  class Fruit {
    static boolean simulateIronJacamarFailFast = false;

    public Fruit() {
       // simulate IronJacamar transaction_fail_fast that normally happens when getting a DB connection from connection pool, instead we want
       // the exception to be thrown when EntityManager.find() is loading the found Fruit entity from DB.  Might also try throwing a GenericJDBCException instead of PersistenceException
       if ( simulateIronJacamarFailFast ) {
           throw new PersistenceException("org.hibernate.exception.GenericJDBCException: Unable to acquire JDBC Connection", due to IJ throwing "javax.resource.ResourceException: IJ000459: Transaction is not active: tx=Local transaction");
       }
    }

    static public void clearSimulationFlag() {
        simulateIronJacamarFailFast = false;
    }

    static public void enableSimulationFlag() {
        simulateIronJacamarFailFast = true;
    }


	Long id;

	@Id
	@GeneratedValue
	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}
}