SQL injection leads to exception instead of error message

Precondition

• install Web Developer plugin for your browser

Steps to reproduce:

1. Login and open Create Topic page
2. Go to "Ending date" field.
3. Convert the field to textarea using WebDeveloper plugin (Forms -> Convert Text Inputs to Textsreas)
4. Type any sql-injection, for example: 1' OR '1'='1
5. Press "Save" button

Actual result: Following error message appears:

Failed to convert property value of type java.lang.String to required type org.joda.time.DateTime for property topic.poll.endingDate; nested exception is java.lang.IllegalArgumentException: Invalid format: "1 OR 1=1" is malformed at " OR 1=1"   

Expected result: user-friendly error message is shown, for ex.
EN: "Please, choose the correct date"
RU: "Пожалуйста, выберите корректную дату"