[OO Support Tip] Is HPOO affected by Leap Second Event on June 30, 2015?
Java does not handle leap seconds itself but it relies on the time provided by the operating system. Therefore, a Java application is unaware of this event.
However, there may be a hypothetical situation when during a flow run you have steps that execute during second 59 and the leap second. In this case, you may observe them in the Run History/Explorer in a different order than their temporal order of execution. Similar issues in other subsystems (logs) may be observed when events happen during those two seconds (59 and 60) and data is being displayed chronologically.
What is more important is that flow schedules will not be affected. Also, Terracotta Grid Servers will not be affected.
More noticeable problems may occur on some Linux systems running unpatched Kernel versions 2.2.26 to 3.3 (inclusive) where high CPU consumption will be observed after the NTP client inserts the leap second. In this case, there is a workaround here: https://ma.ttias.be/a-fix-for-the-java-leap-second-bug/
Additionally, HP does offer the tzupdater v1.4.11 tool (but this update despite mentioning the leap second does not handle the leap second):
Knowing about this tool is still important since any HP Java solution should be up to date with the latest time zone/DST changes. In case you encounter time zone issues, think about this as well.