io exception is checked or unchecked code example
Example 1: What are checked Exceptions
1) All the subclasses of Throwable class except error,Runtime Exception and
its subclasses are checked exceptions.
2) Checked exception should be thrown with keyword throws or should be provided
try catch block, else the program would not compile. We do get compilation
error.
Examples :
1) IOException,
2) SQlException,
3) FileNotFoundException,
4) InvocationTargetException,
5) CloneNotSupportedException
6) ClassNotFoundException
7) InstantiationException
Example 2: Unchecked exception
All subclasses of RuntimeException are called unchecked exceptions.
These are unchecked exceptions because compiler does not checks if a method
handles or throws exceptions. Program compiles even if we do not catch the
exception or throws the exception. If an exception occurs in the program,
program terminates. It is difficult to handle these exceptions
because there may be many places causing exceptions.
Example :
1) Arithmetic Exception
2) ArrayIndexOutOfBoundsException
3) ClassCastException
4) IndexOutOfBoundException
5) NullPointerException
6) NumberFormatException
7) StringIndexOutOfBounds
8) UnsupportedOperationException
Example 3: how to handle checked exceptions in java
I would either handle or declare. I Declare using THROWS keyword or handle by
using TRY&CATCH block. If I will use it again I would handle it. If it will
occur only once than I would use THROWS keyword
Example 4: Can we use catch statement for checked exceptions
If there is no chance of raising an exception in our code then we can’t
declare catch block for handling checked exceptions. This raises compile time
error if we try to handle checked exceptions when there is no possibility
of causing exception.