JPA uso exception CommunicationsException erro This exception is never thrown

[paribe]

Olá,

não entendi porque me dá erro abaixo na linha do ccx

Porque ???

abs

Unreachable catch block for CommunicationsException. This exception is never thrown 
 from the try statement body

try{
			//----------------------------------------
			try{
				
				try{
				    manager = PersistenceServiceFactory.getInstance().getManager();
				    System.out.println("Valor de em ="+manager);
				} catch (CommunicationsException ccx) {
					throw new PersistenceException("Erro acesso arquivo persistence.xml (Facade)" +ccx,ccx.toString(),null);
				}