Tomcat pool connection leaks preceded by "Pre-bound JDBC Connection found" / "No value for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" errors in EWS

Issue

• Repeating failures such as the following are observed

  [ajp-apr-127.0.0.1-8209-exec-12] 2016-09-16 14:14:07,351 EDT ... org.springframework.transaction.IllegalTransactionStateException: Pre-bound JDBC Connection found! JpaTransactionManager does not support running within DataSourceTransactionManager if told to manage the DataSource itself. It is recommended to use a single JpaTransactionManager for all transactions on a single DataSource, no matter whether JPA or JDBC access.
          at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:357)
          at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:372)
          ...
  ...
  [ajp-apr-127.0.0.1-8209-exec-12] 2016-09-16 14:15:04,561 EDT ... java.lang.IllegalStateException: No value for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@18b256d6] bound to thread [ajp-apr-127.0.0.1-8209-exec-12]
          at org.springframework.transaction.support.TransactionSynchronizationManager.unbindResource(TransactionSynchronizationManager.java:209)
          at org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter.doFilterInternal(OpenEntityManagerInViewFilter.java:185)
          ...
  

• Eventually, exceptions such as the following begin to occur

  [ajp-apr-127.0.0.1-8209-exec-1] 2016-09-16 14:28:46,518 EDT ... org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.tomcat.jdbc.pool.PoolExhaustedException: [ajp-apr-127.0.0.1-8209-exec-1] Timeout: Pool empty. Unable to fetch a connection in 30 seconds, none available[size:150; busy:150; idle:0; lastwait:30000].