javax.validation.ValidationException: HV000041: Call to TraversableResolver.isReachable() threw an exception

The stack trace shows your hashcode method is throwing an NPE :

Caused by: java.lang.NullPointerException at com.dem.model.DeploymentConfigurationMappingPK.hashCode(DeploymentConfigurationMappingPK.java:79) at 

You need to fix your hashCode method to handle the null.