Message Title

But when I'm trying to validate it using the hibernate validator I receive an exception:

javax.validation.ValidationException: HV000041: Call to TraversableResolver.isReachable() threw an exception.
	at org.hibernate.validator.internal.engine.ValidatorImpl.isValidationRequired(ValidatorImpl.java:1257)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:459)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:406)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:370)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:322)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateCascadedConstraint(ValidatorImpl.java:625)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateCascadedConstraints(ValidatorImpl.java:490)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:331)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:152)
...
Caused by: java.lang.NullPointerException
	at ch.voev.oevp.services.wegsuche.serviceobjects.WegAnfrage.hashCode(WegAnfrage.java:223)
	at org.hibernate.validator.internal.engine.resolver.SingleThreadCachedTraversableResolver$TraversableHolder.buildHashCode(SingleThreadCachedTraversableResolver.java:153)
	at org.hibernate.validator.internal.engine.resolver.SingleThreadCachedTraversableResolver$TraversableHolder.<init>(SingleThreadCachedTraversableResolver.java:114)
	at org.hibernate.validator.internal.engine.resolver.SingleThreadCachedTraversableResolver$TraversableHolder.<init>(SingleThreadCachedTraversableResolver.java:96)
	at org.hibernate.validator.internal.engine.resolver.SingleThreadCachedTraversableResolver.isReachable(SingleThreadCachedTraversableResolver.java:41)
	at org.hibernate.validator.internal.engine.ValidatorImpl.isValidationRequired(ValidatorImpl.java:1248)

Problem is that validator invokes hashCode() method with null mandatory field. But purpose of validator is to check nullability of this field and produce a validation error. Current behaviour is conceptually wrong from my point of view.