This note will list few things you should try to avoid in your design. Please also see notes on SOLID Principles and summary of additional design principles and best practices.

1. Run-Time Type Identification (RTTI)

   • Design that require you to check for the actual type of the reference object should be avoided (e.g. if(type(something) = something, do something). 

2. Cyclomatic complexity (CC)

SOLID is a mnemonic acronym introduced by Michael Feathers for five of the principles named by Robert C. Martin, and when applied together, these intend to make it more likely that a programmer will create a system that is easy to maintain and extend over time.

1. (++) Single responsibility principle (SRP)

   • ​Every class should have a single responsibility, and that responsibility should be entirely encapsulated by the class. All its services should be narrowly aligned with that responsibility. 

Enterprise Java Bean (EJB)

Enterprise Java Bean (EJB) was the Java EE way for creatng enterprise applications without worrying about middleware requirements such as transaction management, persistence, security, distribution, remoting etc. 

The older EJB programming model however had many problems and POJO programming model emerged as an alternative means to solve those problems. 

Exceptions should be preferred over error codes as returning error codes will force you to have an “if” statement to check for error code, which may be confusing to some readers and there is also a chance that the caller may forget to check for error codes. If you use error codes, you will also need to have some class that defines all error codes. 

Is formatting your code important? Formatting your code properly is as important as working code. Proper formatting increases readability and hence maintainability, and also give readers the impression that the code was written by professionals.  Let us quickly see some of the formatting issues from vertical as well as horizontal perspectives.