Every primitive type is a problem. General purpose programming languages are too "general-purpose" to be useful. Java will happily let you add two integers even

Every primitive type is a problem. General purpose programming languages are too "general-purpose" to be useful. Java will happily let you add two integers even though one may represent a quantity in metric and the other in imperial. Invariably you should create your own DSL-like layer to organize your code and enforce consistency and correctness.