Is Connection.setSchema() (JDBC4) supported?

[edysli]

Hi,
I've tried using Connection.setSchema() in my code but got an AbstractMethodError exception:

java.lang.AbstractMethodError: com.mchange.v2.c3p0.impl.NewProxyConnection.setSchema(Ljava/lang/String;)V

This occurs with version 0.9.5-pre2 and 0.9.5-pre3-SNAPSHOT.
So is Connection.setSchema() supposed to be supported?

[swaldman]

hi,

setSchema() is supported by 0.9.5-pre3-SNAPSHOT. If you are seeing an AbstractMethodError in 0.9.5-pre3-SNAPSHOT, it is likely because your driver fails to support the method. The error you report above was, I'd be willing to bet, generated under 0.9.2.x or a previous version. Here's a very similar error, generated under 0.9.5-pre3-SNAPSHOT against postgresql-8.2-504.jdbc3.jar:

java.lang.AbstractMethodError: org.postgresql.jdbc3.Jdbc3Connection.setSchema(Ljava/lang/String;)V

Note the distinction -- under 0.9.5-pre3, the abstract method error still occurs but in the JDBC driver's Connection object rather than in com.mchange.v2.c3p0.impl.NewProxyConnection. With a more recent postgres driver, postgresql-9.2-1002.jdbc4.jar, the error is only slightly more informative:

java.sql.SQLFeatureNotSupportedException: Method org.postgresql.jdbc4.Jdbc4Connection.setSchema(String) is not yet implemented.

Please recheck under 0.9.5-pre3-SNAPSHOT. Verify that the build you are running is indeed a 0.9.5-pre3-SNAPSHOT [look in your logs for a line like "Initializing c3p0-0.9.5-pre3"], and inspect the error message carefully. Are you sure the AbstractMethodError you see is coming from com.mchange.v2.c3p0.impl.NewProxyConnection rather than a JDBC driver class?

c3p0-0.9.5-pre3 should support all JDK 1.7 / JDBC 4 methods now, but only if the underlying driver also supports them.

[edysli]

I ran a new build of my project and I confirm it uses 0.9.5-pre3-SNAPSHOT. Here are the log lines from c3p0's startup:

5022 [MLog-Init-Reporter] INFO  com.mchange.v2.log.MLog - MLog clients using log4j logging.
5371 [main] INFO  com.mchange.v2.c3p0.C3P0Registry - Initializing c3p0-0.9.5-pre3 [built 19-May-2013 07:22:27 -0700; debug? true; trace: 10]

I'm using HSQL 2.2.9 and, if I read it's javadoc correctly (http://hsqldb.org/doc/2.0/apidocs/org/hsqldb/jdbc/JDBCConnection.html), it should implement setSchema. The first line of the error is still:

java.lang.AbstractMethodError: com.mchange.v2.c3p0.impl.NewProxyConnection.setSchema(Ljava/lang/String;)V

This project also uses Hibernate (4.2) and Spring Framework (3.2) so maybe some other dependency is causing the problem... If it helps, I can try to create a small project with the same dependencies to reproduce the error.

Below is the full stack trace of one such error:

java.lang.AbstractMethodError: com.mchange.v2.c3p0.impl.NewProxyConnection.setSchema(Ljava/lang/String;)V
    at my code (DAO)
    at org.hibernate.jdbc.WorkExecutor.executeWork(WorkExecutor.java:54)
    at org.hibernate.internal.SessionImpl$2.accept(SessionImpl.java:1981)
    at org.hibernate.internal.SessionImpl$2.accept(SessionImpl.java:1978)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.coordinateWork(JdbcCoordinatorImpl.java:284)
    at org.hibernate.internal.SessionImpl.doWork(SessionImpl.java:1999)
    at org.hibernate.internal.SessionImpl.doWork(SessionImpl.java:1985)
    at my code (DAO)
    at my code (DAO)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
    at com.sun.proxy.$Proxy34.myMethod(Unknown Source)
    at my code (service)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.aop.interceptor.PerformanceMonitorInterceptor.invokeUnderTrace(PerformanceMonitorInterceptor.java:62)
    at org.springframework.aop.interceptor.AbstractTraceInterceptor.invoke(AbstractTraceInterceptor.java:111)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
    at com.sun.proxy.$Proxy38.myMethod(Unknown Source)
    at my code (controller)
    at my code (integration test)

[swaldman]

hi,

if you can send a small demonstration, that would be fantastic.

setSchema( ... ) really is in the generated code for NewProxyConnection, and when i call the method, it clearly does get through the c3p0 layer (only to fail at my underlying driver ). so this is very puzzling.

[edysli]

I managed to make a demonstration project for this error. It is available here https://github.com/edysli/c3p0_AbstractMethodError_demo. Run mvn test (on Java 7) and the exception should appear.

Looks like you already fixed it though; I accidentally ran Maven with --update-snapshots, it downloaded a new snapshot and I got a different exception. :) I can still trigger the AbstractMethodError with 0.9.5-pre2.

[swaldman]

Wow. You are right. A quick javap confirms that c3p0-0.9.5-pre2's NewProxyConnection includes only JDBC3 methods, while c3p0-0.9.5-pre1 and c3p0-0.9.5-pre3-SNAPSHOT properly includes all JDK1.7 methods. I'm not sure how this happened; I must have had an JDBC library somehow shadow JDBC4 libs when I built, although that should be hard since c3p0-0.9.5-preX won't build in anything but 1.7. This build quirk may remain a mystery, but I'll go ahead and make c3p0-0.9.5-pre3 a release to cover up the shame and embarrassment. :) And I'll be sure to test for the presence of JDBC4 methods going forward.

Thank you for the demo project. I had to edit the aspectj.version property to 1.7.2 rather than 1.7.2-RELEASE, but other than that it worked fine. (Of course I played around with c3p0 versions.) Except for in -pre2, the error I'm now getting is org.hibernate.exception.SQLGrammarException inside hsqldb libs.

[edysli]

Thank you for fixing it! :)