Exceptions

Exceptions (e.g. SQLException) thrown in the backend cannot be passed to GWT and therefore the original exception can not be accessed in the frontend.
However our own exceptions are known by GWT and can be accessed. To show the original exception message in the frontend, an Exception Parser is introduced. The Exception Parser reformat the original exception message to an HTML string. This string can be set as message on our own exceptions, so that the it can be shown in the frontend.