Java apps like JIRA emit stacktraces when things go wrong. Inside a stacktrace, the most important 'signature' part is the classname:linenumber part, eg. ConsistencyCheckImpl.java:94 in the stacktrace:
java.lang.NullPointerException
at com.atlassian.jira.upgrade.ConsistencyCheckImpl.initialise(ConsistencyCheckImpl.java:94)
at com.atlassian.jira.upgrade.ConsistencyLauncher.contextInitialized(ConsistencyLauncher.java:27)
Unfortunately, searching for 'ConsistencyCheckImpl.java:94' in JIRA does not return any hits (on jira.atlassian.com, this is in a comment on JRA-5371).