* Remove catch clauses, throw exceptions in GET methods
* Remove BusinessObjectRessource.class
* Move constants form BusinessObjectRessourceClass to subclasses

* Implement conversion of related BOs from Json
* Implement method BusinessObject.equalsInAllProperties
* Fixed spelling mistake in test resource TestApplication.json

* Replace hard coded relation fields by Map of relations
* Make methods in subclasses generic, move to super class

* Use DatabaseControllerHelper extends DatabaseController for test
cases. This keeps track of all created BOs during the tests, so they can
be deleted by @AfterClass method.
* Refactor the relation storing tests to use a Dataprovider - remove
duplicate code.

* Make DatabaseController and SqlStatements classes non-static
* Rename SqlStatements to SqlStatementFactory
* Make Connection a field of SqlStatementFactory, so there are no longer
new connections for every request

* Made methods generic, removed unneeded code
* Dropped SELECT_Statements.xml, added two statements to
SQL_Statements.xml

* Implement DatabaseController method to delete BusinessObject
* Implement DatabaseController method to update BusinessObject
* Commit missing file with SQL statements
* Adjusted TestCreateScript with ON DELETE constraints
* Splitted DatabaseControllerTest by introducing
DatabaseControllerDataProvider and DatabaseControllerRelationsTest

* Implement DatabasoController.storeToDB method
* Use java Uuid class to generate random ids; adjust SQL Create Script
to varchar(64) ids
* Refactor SignletonUtil (did not work as expected)

* Implement method DatabaseController.checkIfExistsInDB(), to check if a
BusinessObject with given ID already exists in the Database
* Intoduced NullBusinessObject class (NullObject pattern) 

* Move BusinessObjectFactory to model package
* Extract constants for table names and JSON keys
* Implement conversion from JSON to Java Objects

* Add sample JSONs for feature and category as text files
* Implement JSON conversion for Feature and Category
* Refactored JSON conversion, moved generic parts to super class

* Move general test from ApplicationTest to BusinessObjectTest
* Added abstract convertToJson() to BusinessObject
* Implement convertToJson() method for Applications
* Implement FileUtil.readFile to read text files for testing purpose
* Added sample JSON as text file

* Implement method to check if a JSONObject contains all the elements of
an other
* Implement method to check if two JSONObjects contain all the elements
of each other
* Implement Assertion that fails if two JSONObjects do not contain all
the elements of each others