T.I.L_221223

What’s New for Today

1. Effective Java
   • exception
     • use exceptions only for exceptional conditions
       • not use in ordinary control flows
       • state-dependent, state-test methods
       • optional
     • use checked exceptions for recoverable, unchecked exceptions for other cases
     • avoid unnecessary use of checked exception
       • checked exceptions mandate programmers to catch errors –> pros and cons but it clutters the program
       • dependency issue –> service - repository service has to catch technical errors
     • favor use of standard exceptions
       • most of exceptions are already implemented
       • easy to use, maintain
     • throw exceptions appropriate to abstraction
       • higher classes can’t predict lower classes’ exception –> due to inheritance
       • transfer it to higher exception case
       • consider using exception chaining
     • document all exceptions
     • include failure-capture informations
       • error information must contain all of the parameters related to exception
     • strive for failure-atomicity
       • even though the method end successfully, the state must be consistent before and after the method execution
       • use copy of input paramters rather directly using them
       • check parameter before method execution
     • don’t ignore exceptions
       • unhandled exceptions can slowly make the program dead