EXCEPTION

• what is exception?
  an exception is an abnormal event that occurs during the execution of a program which disrupts the normal flow of instructions. In simpler words, it’s a problem or error that happens while your program is running.

  • why use ?

       We use exceptions in Java to handle errors and abnormal situations gracefully, instead of letting the program crash. Think of exceptions as a safety net for your program.     
    

    • when use exception?

       ou use exceptions whenever there’s a chance that the user might enter data in the wrong format, which would normally crash your program.
      

    Error

    1) System-level serious problem
    
    2) Cannot handle
    
    3) JVM, memory, hardware
    
    4) Examples OutOfMemoryError, StackOverflowError
    
    5) Usually program crash

     exception
    

    1) abnormal event
    2) Can handle using try-catch
    3) Programmer mistake, unexpected input
    4) ArithmeticException, NullPointerException
    5) Can continue if handled

Throw, and Try...Catch...Finally

The try statement defines a code block to run (to try).

The catch statement defines a code block to handle any error.

The finally statement defines a code block to run regardless of the result.

The throw statement defines a custom error.

Reffer;
https://www.w3schools.com/js/js_errors.asp