[JCS-113] Potential NPE in JDBCDiskCache

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: jcs-2.0-beta-1
• Assignee: Thomas Vandahl
• Reporter: Sebb
• Created: 03/Apr/14 18:59
• Updated: 01/Apr/15 14:50
• Resolved: 06/Jun/14 13:51

Description

The test JDBCDiskCacheManagerUnitTest fails with an NPE if debug logging is enabled.

java.lang.NullPointerException
at org.apache.commons.jcs.auxiliary.disk.jdbc.JDBCDiskCache.getSize(JDBCDiskCache.java:982)
at org.apache.commons.jcs.auxiliary.disk.jdbc.JDBCDiskCache.getStatistics(JDBCDiskCache.java:1146)
at org.apache.commons.jcs.auxiliary.disk.AbstractDiskCache.getStats(AbstractDiskCache.java:525)
at org.apache.commons.jcs.auxiliary.disk.jdbc.JDBCDiskCache.toString(JDBCDiskCache.java:1251)
at org.apache.commons.jcs.auxiliary.disk.jdbc.JDBCDiskCacheManagerAbstractTemplate.getCache(JDBCDiskCacheManagerAbstractTemplate.java:119)
at org.apache.commons.jcs.auxiliary.disk.jdbc.JDBCDiskCacheManager.getCache(JDBCDiskCacheManager.java:117)
at org.apache.commons.jcs.auxiliary.disk.jdbc.JDBCDiskCacheManagerUnitTest.testGetCache_normal(JDBCDiskCacheManagerUnitTest.java:49)

That happens because the getSize() method calls

getPoolAccess().getConnection()

and getPoolAccess() may return null if the initializePoolAccess method called by the constructor fails to set up the pool.

It is trivial to check if the poolAccess field has been set up and avoid the NPE in getSize(). However, the getPoolAccess() method is used extensively within the class, and also externally as well.

It looks as though the class is barely usable if the field cannot be initialised, so it might perhaps be better if the constructor threw an Exception of some kind.