validation on commit

org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction
	at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:522)
	at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:755)
	at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:724)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:475)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:270)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at com.sun.proxy.$Proxy152.update(Unknown Source)
	at com.myclient.servlet.rest.Rest.updateObjects(Rest.java:323)
	at com.myclient.servlet.rest.Rest.parseAndUpdateObjects(Rest.java:307)
	at com.myclient.servlet.rest.Rest.doPost(Rest.java:226)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.myclient.servlet.ThreadContextFilter.doFilter(ThreadContextFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:724)
Caused by: javax.persistence.RollbackException: Error while committing the transaction
	at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:92)
	at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:513)
	... 32 more
Caused by: javax.validation.ConstraintViolationException: Validation failed for classes [com.myclient.model.User] during update time for groups [javax.validation.groups.Default, ]
List of constraint violations:[
	ConstraintViolationImpl{interpolatedMessage='A password is required when saving or creating a user.', propertyPath=password, rootBeanClass=class com.myclient.model.User, messageTemplate='{com.myclient.model.User.password.NotNull}'}
]
	at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:159)
	at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreUpdate(BeanValidationEventListener.java:102)
	at org.hibernate.action.internal.EntityUpdateAction.preUpdate(EntityUpdateAction.java:228)
	at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:115)
	at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:377)
	at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:369)
	at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:287)
	at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:339)
	at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:52)
	at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1234)
	at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:404)
	at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
	at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:175)
	at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:75)
	... 33 more