OOPS

Exception v/s Error

Exception	Can be handled.
Error	No solutions to a problem.

Error

Examples:

• Memory failure (RAM).
• Accessing unavailble data.
• Power failure error.

Exception Handling

Examples:

1. Something which is checked (or already known) to handle that situation.

Can be handled by self & so is checked.

1. Unchecked + Errors

Checked, but cannot be handled by self.

Compile - Time Exception

a.k.a. “Checked Exception”

Compiler / Interpreter knows. Also, the programmer knows how to handle it.

• Using variable without declaring it.
• Trying to change/re-assign const identifier.
• Syntax error.
• Treating local variable as a global variable.

Runtime Exception

a.k.a. “Unchecked Exception”

• Index out of bound exeption.
• Condition not terminated.
• Arithmetic exception.
• Using freed memory.
• De-refrencing NULL or dangling pointer.
• Memory leak.
• Uncompatile exception.
• ENF / DNF.
• Class not found.

These are unchecked but still resolved only by the programmer’s help. Only some exceptions can be handled with the help of compiler.

5 Keywords

There are 5 keywords for exception handling in most programming languages.

• try
• catch
• throw
• throws
• finally

We cannot try without catch. We cannot catch without try.

Exception Chaining

• Some exceptions are useful to us in a particular situation / time.
• So that paricular exception can be handled at a particular & desired situation & time.
• Thus, we chain exceptions up.