Grails 2.4.4 : PooledConnection has already been closed - java-8

Question

I have been trying to upgrade my project from grails 2.1.2 to grails 2.4.4. This project calls another module(upgraded to java 8) which uses ibatis for database connection. While the module as a standalone works fine, it gives me "Connection Closed" exception when accessed from the grails project.
This applications had been working fine on grails 2.1.2 with java 6. However, the upgrade seems to be breaking something.
Exception:
Caused by: java.sql.SQLException: PooledConnection has already been closed.
at org.apache.tomcat.jdbc.pool.DisposableConnectionFacade.invoke(DisposableConnectionFacade.java:86)
at com.sun.proxy.$Proxy35.prepareStatement(Unknown Source)
at sun.reflect.GeneratedMethodAccessor354.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1270)
at org.springframework.jdbc.datasource.LazyConnectionDataSourceProxy$LazyConnectionInvocationHandler.invoke(LazyConnectionDataSourceProxy.java:376)
at com.sun.proxy.$Proxy37.prepareStatement(Unknown Source)
at sun.reflect.GeneratedMethodAccessor354.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1270)
at org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy$TransactionAwareInvocationHandler.invoke(TransactionAwareDataSourceProxy.java:240)
at com.sun.proxy.$Proxy37.prepareStatement(Unknown Source)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.instantiateStatement(PreparedStatementHandler.java:87)
at org.apache.ibatis.executor.statement.BaseStatementHandler.prepare(BaseStatementHandler.java:88)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.prepare(RoutingStatementHandler.java:59)
at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:85)
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:324)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:136)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1270)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:434)
I have searched for other similar questions online but I dont seem to be facing any of the issues mentioned. I do not see any Abandoned connections in my logs. Also from the DB side I see that there are two connections still alive(minimum idle connection is set to 2).
DataSource.config:
dataSource {
pooled = true
driverClassName = "oracle.jdbc.driver.OracleDriver"
username = xxx
password = yyy
dialect = 'org.hibernate.dialect.Oracle10gDialect'
dbCreate = "none"
properties {
maxActive = 15
maxIdle = 5
minIdle = 2
initialSize = 8
minEvictableIdleTimeMillis = 60000
timeBetweenEvictionRunsMillis = 60000
maxWait = 10000
testOnBorrow = true
validationQuery = "select 1 from dual"
}
}
EDIT 1:
After some more debugging on my side I see that the issue happened after we upgraded our tomcat plugin to version 7.0.55. Earlier we were using 2.1.2. This new plugin uses jdbc-pool through JdbcInterceptor to create the DB connections. This connection is then being sent to the second module(which uses ibatis)
EDIT 2: SOLVED
We tried to create a different datasource around the above mentioned datasource config pointing it to c3p0 and placed it in resources.groovy. This was injected to the ibatis module and we saw that this time round there was no "Connection Pool closed" error. It seems like some issue with the jdbc-pool, but we would like to know if there is some other workaround.
New config in resources.groovy:
dataSource_new (ComboPooledDataSource) { bean ->
idleConnectionTestPeriod = 1 * 60 * 60
testConnectionOnCheckin = true
bean.destroyMethod = 'close'
user = xxx
password = yyy
driverClass = <same as in datasource>
jdbcUrl = zzz
}
BuildConfig.groovy: compile('com.mchange:c3p0:0.9.5.1')