Testing this, the code is right and the comment is wrong. I'll fix the comment. Changing it to replace `"+"` with `" "` give:

    {"message":"Date 9999-01-01T00:00:00 0100 cannot be parsed as UTC millis or using format yyyy-MM-dd'T'HH:mm:ssZ","details":"java.lang.IllegalArgumentException: Date 9999-01-01T00:00:00 0100 cannot be parsed as UTC millis or using format yyyy-MM-dd'T'HH:mm:ssZ\n\tat brooklyn.rest.resources.UsageResource.parseSafely(UsageResource.java:226)\n\tat brooklyn.rest.resources.UsageResource.getApplicationUsage(UsageResource.java:69)

Unrelated note: I don't think we should be returning stacktraces to the REST api caller like this; it's a security vulnerability.