Clicking on "Greenhopper" link in admin to enter license fails with stack trace

Steps:
1. Start JIRA with Greenhopper plugin.
2. Restore the data in setup screen.
3. Goto Administration tab and click on "Greenhopper" link.

Result:
1. It fails with "java.lang.NoClassDefFoundError: java/util/Date
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2427)
at java.lang.Class.privateGetPublicMethods(Class.java:2547)
at java.lang.Class.getMethods(Class.java:1410)

2. Restart JIRA and try again it work without any error.

Expected:
1. User should be able to input license for GH without any issues.