[Java] Exceptions

Tihs study about exception is not including any practice concerning practice only for exception will be lead to rabbit hole. I'll look it again when I have to.

Names

• Exception: Errors occuring during runtime or compile time.
• Purpose of Exception: Prevents the program to be not quitted in abnormal ways.
• Lists: Types of Exception(depends on when it happens)
  • Checked Exception: Exceptions that must be dealt during compile.
  • Unchecked Exception: Not mandatory. Occurs during runtime.
• Lists: Heirarchy of Exception Class
  • Throwable
    • Error: Serious error on system level.(ex. OutOfMemoryError, StackOverflowError)
    • Exception: Exceptions that can be dealt on app level(ex. checked/unchcked exception)
• try: area for code might occuring exception.
• catch: deals the error from above.
• finally: area for code should be finally ran. Mostly used for closing resources. (file close, DB connection close)
• throws: Declares the method can throw exceptions so that the caller of the method can deal with it.
• CustomException: User defined exception implemented by extending Exception class.