no effective code change - fixed warnings about serialization, override, raw-types (#1032)

src/test/java/org/tests/model/basic/OEngine.java

@@ -4,10 +4,12 @@ import javax.persistence.Entity;
 import javax.persistence.Id;
 import javax.persistence.OneToOne;
 import javax.persistence.Version;
+
+import java.io.Serializable;
 import java.util.UUID;
 
 @Entity
-public class OEngine {
+public class OEngine implements Serializable {
 
   private static final long serialVersionUID = 1L;