Exceptions or OCA

Question 1

how many types of exceptions to be recognized

Answer 1

runtime exceptions, checked exceptions and errors

Question 2

what is exception

Answer 2

is an event alters the program flow, un wanted event

when occur in execution the program

Question 3

exceptions are objects?

Answer 3

yes

Question 4

behind the exceptions generating?

Answer 4

1. object created by the JVM

2. thrown to the program

Question 5

throw keyword?

Answer 5

is used throwing the exception manually,
throw aib(object name)--->JVM by using this keyword 
we can see the exception code in councel.

Question 6

how could be prove that exceptions are class and throw keyword

Answer 6

for ex;  ArithmeticExceptions art= new ArithmeticExceptions();
throw art; // JVM how throw it to program.....

Question 7

what is the try keyword—-(try catch block)

Answer 7

try {

some code written} catch (name of the exceptions subject name)

Question 8

if we change the catch- with other exceptions does it work?

Answer 8

no it does not catch anything,-so IndexOutOfBOund Exceptions- not catch the Arithmetics Exceptions

Question 9

can I add second catch block-multi catch buyer?

Answer 9

yes, it is goingto be same, catch() System.out…

catch()System out….

Question 10

what is the more one to cover all exceptions like arithmetics, indexoutof bound…

Answer 10

Exception—instead of arithmeticsExceptions, replace the exceptions…

Question 11

how many types exceptions

Answer 11

uncheked exceptions(runtime exceptions)
checked exceptions(Exception and subclasses)

Question 12

handle or declare rule

Answer 12

Java requires the code either handle or declare in the method signature

Question 13

difference between Errors and Exception?

Answer 13

Errors indicate serious problems that does not try and catch, Exceptions indicates the situation that can try and catch_
both is child class of throwable

Question 14

Exceptions—Checked?runtime exceptions

Answer 14

Checked exception must be handled before we can run the program. If ignored then program won’t compile.

Question 15

Unchecked Exceptions/Runtime Exception

Answer 15

Type of exception where will be thrown during runtime.

It is very challenging to predict. Because it won’t complain during compile time.

Question 16

how handle exceptions

Answer 16

throws Exception,

try and catch block

Question 17

multiple Catch block rules

Answer 17

When using multiple catch blocks, Parent Exception type MUST be used in the end. Otherwise child exception catch blocks will be ‘Unreachable code’ and it won’t be compiled.
​Use pipe line ”|” between exceptions when throwing multiple exceptions.
​if there are multiple catch block, when exception is caught by first catch block, rest of the catch block will NOT catch any exception.

Question 18

difference between throw and throws?

Answer 18

throw –> explicitly creating exception(tell Java that u want throw the exception
throws –> passing the exception to next user to handle(that the method might throw an exception

Question 19

adding finally block

Answer 19

try{//code} catch(exception identifielder){} finally{}
if exceptions is thrown finally block run after catch block;
no exceptioons is thrown after try block complete

Question 20

Run time exceptiosn

Answer 20

ArithmeticExceptions/IndexOutofBound Exception/NullPointerException/

Question 21

Checked Exceptions

Answer 21

IOException/FIleNotFoundException

Question 22

Errors

Answer 22

Errors extend the Error class. StackOverFlowError,NoClassDeFoundError/

Question 23

sample for writing throw keyword

Answer 23

throw new Excep();
throw new Excep("oh hey");

Question 24

how to read the code

Answer 24

start top try block and ctach if there is any exceptions of not pass to the finally blocks

Question 25

which exceptions handle by the JVM

Answer 25

Aritmethic Exc—divided by 0;
ArrayIndexOutOfBounds—illegal index
ClassCastExceptions–cast an objto suclass not instance
NullPointerException—

Question 26

Runtime Exceptiond/Uncheked

Answer 26

not have be handled or declared