Make Jira run under Java 1.5

Unfortunately Jira will not run under the 1.5 JVM, although all appears well,
the scheduler fails to start:
[INFO] QuartzScheduler - -Scheduler JiraQuartzScheduler_$_NON_CLUSTERED
started.
Exception in thread "QuartzSchedulerThread" java.lang.ClassCastException:
java.util.Date
at java.sql.Timestamp.compareTo(Timestamp.java:474)
at org.quartz.Trigger.compareTo(Trigger.java:611)
at org.quartz.simpl.TriggerComparator.compare(RAMJobStore.java:904)
at java.util.TreeMap.compare(TreeMap.java:1093)
at java.util.TreeMap.getEntry(TreeMap.java:347)
at java.util.TreeMap.remove(TreeMap.java:506)
at java.util.TreeSet.remove(TreeSet.java:223)
at
org.quartz.simpl.RAMJobStore.acquireNextTrigger(RAMJobStore.java:735)
at
com.atlassian.scheduler.OfBizJobStore.acquireNextTrigger(OfBizJobStore.java:479)
at
org.quartz.core.QuartzSchedulerThread.run(QuartzSchedulerThread.java:197)