Back in Java 1.1 they discovered that the Date function did not fare well when being Internationalized. This is due to the fact that not every country on the planet uses the Gregorian Calendar. Thailand and Taiwan for example both have different calendars.
Sun came up with the Calendar() method to solve this issue.
In LeavesView.java the Date() method is being used even though this is deprecated. This is not recommended.
Here are the references
See the attachment for the exact line numbers of the coding error.