Adjust checkstyle rules. Make checkstyle fail the build when violations are found. Correct all current checkstyle violations.

service-layer/src/main/java/com/iluwatar/servicelayer/spell/SpellDaoImpl.java

@@ -27,8 +27,9 @@ public class SpellDaoImpl extends DaoBaseImpl<Spell> implements SpellDao {
       result.getSpellbook().getWizards().size();
       tx.commit();
     } catch (Exception e) {
-      if (tx != null)
+      if (tx != null) {
         tx.rollback();
+      }
       throw e;
     } finally {
       session.close();