Just bumped up to the latest version (from 1.2.1) and now I'm getting this error, which is causing the transaction to rollback. This was okay on 1.2.1 (no code changes, just a version bump).
java.lang.NullPointerException: null
at com.zaxxer.hikari.proxy.ConnectionProxy._checkClosed(Unknown Source) ~[HikariCP-1.2.3.jar:na]
at com.zaxxer.hikari.proxy.ConnectionJavassistProxy.getAutoCommit(ConnectionJavassistProxy.java) ~[na:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[na:1.7.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_45]
at java.lang.reflect.Method.invoke(Method.java:606) ~[na:1.7.0_45]
at org.springframework.jdbc.datasource.LazyConnectionDataSourceProxy$LazyConnectionInvocationHandler.invoke(LazyConnectionDataSourceProxy.java:376) ~[spring-jdbc-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at com.sun.proxy.$Proxy21.getAutoCommit(Unknown Source) ~[na:na]
at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:68) ~[hibernate-core-4.3.0.Final.jar:4.3.0.Final]
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:162) ~[hibernate-core-4.3.0.Final.jar:4.3.0.Final]
at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1431) ~[hibernate-core-4.3.0.Final.jar:4.3.0.Final]
at org.hibernate.jpa.internal.TransactionImpl.begin(TransactionImpl.java:61) ~[hibernate-entitymanager-4.3.0.Final.jar:4.3.0.Final]
at org.springframework.orm.jpa.DefaultJpaDialect.beginTransaction(DefaultJpaDialect.java:67) ~[spring-orm-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:110) ~[spring-orm-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:380) ~[spring-orm-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
Wrapped by: org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is java.lang.NullPointerException
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:430) ~[spring-orm-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373) ~[spring-tx-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:420) ~[spring-tx-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:257) ~[spring-tx-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95) ~[spring-tx-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:92) ~[spring-data-jpa-1.5.0.M1.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207) ~[spring-aop-4.0.1.BUILD-SNAPSHOT.jar:4.0.1.BUILD-SNAPSHOT]
at com.sun.proxy.$Proxy109.save(Unknown Source) ~[na:na]