Symptom:
    Class not found exception pointing to Apache ‘Datasource’ class

Cause:
    commons-dbcp and commons-pool library jars were not present in i2b2 WEB-INF/lib directory. After some digging I found that in edu.harvard.i2b2.server-common/build.xml, the jboss_pre_deployment_setup target in i2b2 1.7 does not copy all required libraries from src/server-common/lib to deployed lib directory. I verified that in 1.6 installation scripts this was not an issue.

Resolution:
    I manually moved the two required libraries from src/server-common/lib/common to WEB-INF/lib (thus mimicking the expected behavior of the build target) and restarted server which resolved the issue.