Java SQLException Chaining

In JDK 1.4 chained Throwables were added and made logging and tracing exceptions much easier. Being able to create a new exception and specify the causing exception in a standard way, tied to JVM printing out the stack chain, was a big boost to tracking down problems in an application.

There are still some exceptions that do not use this standard chaining mechanism and one of the most frustraiting cases in SQLException. It provides a getNextException() method which returns the next SQLException related to the failed operation. The problem here is without special handling code these nextExceptions just get lost in log messages.

A general solution to this problem is to add an Aspect that either logs the results of getNextException or adds them to the exception chain.

<br />/**<br /> * Copyright 2007 The JA-SIG Collaborative. All rights reserved.<br /> * See license distributed with this file and<br /> * available online at http://www.uportal.org/license.html<br /> */<br />package org.jasig.portal.portlet.dao.jpa;<br /><br />import java.sql.SQLException;<br /><br />import org.apache.commons.logging.Log;<br />import org.apache.commons.logging.LogFactory;<br />import org.springframework.core.Ordered;<br /><br />/**<br /> * Provides additional logging for SQL based exceptions that provide chained exceptions via<br /> * {@link SQLException#getNextException()}<br /> * <br /> * @author Eric Dalquist<br /> * @version $Revision$<br /> */<br />public class SQLNextExceptionLoggerAspect implements Ordered {<br /> protected final Log logger = LogFactory.getLog(this.getClass());<br /><br /> private int order = 0;<br /> <br /> /* (non-Javadoc)<br /> * @see org.springframework.core.Ordered#getOrder()<br /> */<br /> public int getOrder() {<br /> return this.order;<br /> }<br /> /**<br /> * @param order the order to set<br /> */<br /> public void setOrder(int order) {<br /> this.order = order;<br /> }<br /> <br /> public void logBatchUpdateExceptions(Throwable t) {<br /> while (t != null && !(t instanceof SQLException)) {<br /> t = t.getCause();<br /> }<br /> <br /> if (t instanceof SQLException) {<br /> SQLException sqle = (SQLException)t;<br /> <br /> //If the SQLException is the root chain the results of getNextException as initCauses<br /> if (sqle.getCause() == null) {<br /> SQLException nextException;<br /> while ((nextException = sqle.getNextException()) != null) {<br /> sqle.initCause(nextException);<br /> sqle = nextException;<br /> }<br /> }<br /> //The SQLException already has a cause so log the results of all getNextException calls<br /> else {<br /> while ((sqle = sqle.getNextException()) != null) {<br /> this.logger.error("Logging getNextException for root SQLException: " + t, sqle);<br /> }<br /> }<br /> }<br /> }<br />}<br />

This aspect class can be used via Spring's AOP support with the following context configuration:
<br /> <aop:config><br /> <aop:pointcut id="hibernateDaoExecution" <br /> expression="execution(* org.jasig.portal.portlet.dao.jpa.*Dao.*(..))"/><br /> <br /> <aop:aspect ref="sqlNextExceptionLoggerAspect"><br /> <aop:after-throwing pointcut-ref="hibernateDaoExecution" method="logBatchUpdateExceptions" throwing="t"/><br /> </aop:aspect><br /> </aop:config><br /> <br /> <bean id="sqlNextExceptionLoggerAspect" class="org.jasig.portal.portlet.dao.jpa.SQLNextExceptionLoggerAspect" /><br />