The biggest limitation of the Code Gen tool that I've encountered so 
far is that it orders the properties in constructors in its own weird 
way. It doesn't try to preserve the natural order from the .hbm.xml. 
For example, when you see Coordinate3D(10, 20, 30), you expect that 
the order of parameters is (x, y, z), not, for example, (z, x, y)! 
Another problem is when you reference objects w/o using FQN that 
includes the package path - the code generator gets confused and 
generates code that does not compile.