More of the date formatting problems were fixed during the UI updates in 15. I'm going to mark this current bug as fixed. Please open new issues with the 'i18n' label if you encounter further problems.

Just noticed that the KSC custom view (opennms-webapp/src/main/webapp/WEB-INF/jsp/KSC/customView.jsp) displays date/time values for From/To, but they aren't using <fmt:formatDate>.

Here's a patch that adds a new tag <element:formatDate>, and:

1. Converts most uses of <fmt:formatDate> to it.
2. Converts some model classes to use java.util.Date objects instead of java.lang.String.
3. Removes deprecated function formatToUIString(Date) from org.opennms.web.api.Util and org.opennms.netmgt.EventConstants.

I haven't run full unit-tests against this patch.

There were a mixture of display formats used. Some wanted date (SHORT) time (MEDIUM) format. Others wanted date (SHORT), time ("HH:mm:ss"). Some wanted regular whitespace between the two date/time pieces, others wanted &nbsp;

Ben's previous comment is exactly why I marked that Util.formatDateToUIString() method as @deprecated recently. It's fine to use it for now to make things consistent but in the future we'll want to use fmt:formatDate everywhere.

A better fix in the long term is to not use Strings for storing dates in the web element objects, but instead use Date objects directly. Then they can be formatted in the JSP.

Still, this solves it in the short term.