Introduction of Try block

It is highly recomended to handle exceptions .

the code which may rise an exception is called risky code

and we have to define the inside the try block.

coressoponding handling code we have to define inside catch block.

try

{
    Risky code

 }

catch(Exception e)

{

    Handling code

}

    

 Without try block

class Test 

{

    public static void Main(String[] args)

    {

        System.out.println("State1");

         System.out.println(10/0);

          System.out.println("State3");

    }

}

output

with try block

class Test 

{

    public static void Main(String[] args)

    {

        System.out.println("State1");

        try

        {

             System.out.println(10/0);

        }

        catch(ArithmeticException e)

        {

               System.out.println(10/5); 

        }

         System.out.println("State3");      

    }

}

  try

        {

            Sate1;

           Sate2;

          Sate3;

        }

   catch(X e)

        {

              Sate4;

        }

        

within the try block if anywhere exceptions rise  then rest of the try block will not be executed even though we handle that exception .

if state 2 exception rise we cant get sate 3 as output

 Hence within the try block we have to take risky code and the length of try block should as less as possible

example

if we type 1000 lines of code if we get first code exception then rest of the code will not execute 

in addition, to try block there may be the chance of rising exception inside catch and finally blocks .

the way of handling an exception is varied from exception to exception .hence for every exception type it is highly recommended to take separate catch block.

that is .....try with multiple catch blocks is always possible and recommended to use 

try 

{

}

catch  ArithmeticException e)

{

    perform alternative arithmetic operators 

}

catch  (FileNotFoundException e)

{

    use local file

}

catch  (FileNotFoundException e)

{

    use local file

}

This is the best way of programming practice.

Final

final is modifier applicable for class methods and variables.

if a class declares ad final then we cant extend that class 

that s we cant create a child class for that class that is inheritance is not possible for final classes 

if a method is final then we can't override that method in the child class 

if a variable declared as final then we cant perform reassignment for the variable.

Finally

finally is block always associated with try-catch  to maintain clean  up code.

 

try

{
    Risky code

 }

catch(Exception e)

{

    Handling code

}

finally

{

    cleanup code

}

the specialty of finally block is it will be executed always respective whether exception rise or not whethert handle or not 

Finalize()

finalize is a method always invoked by garbage collector just before destroying object to perform clean up activities once finalize method complete immediately garbage collector destroys the object .

in try-catch-finally  order is important 

whenever we writing try compulsory we should try either  catch or finally otherwise we will get a compile-time error 

whenever we writing catch block   compulsory we should write try block 

that is catch without try invalid

whenever we writing finally block compulsory we should write try block

for try-catch-finally   block curly brackets are mandatory