Possible Duplicate: Anyone else experiencing high rates of Linux server crashes during a leap second day? On last Saturday(31 June 2012), Java applications suddenly started to use 100% CPU like described in this on some servers. The problem was recovered after restarted tomcat. It's similar to Java leap second bug but it happened during day not midnight. The time was around 17:35(GMT+9) on 31 June. Can cause of this problem be leap second?