exxxcepppppppption

Question 1

What does Exception and Error extend?

Answer 1

Class called Throwable

Question 2

What is the sub class of Throwable?

Answer 2

Exception and Error

Question 3

What is the sub class of Exception

Answer 3

RunTimeException

Question 4

What are runtime exception? They are also known as?

Answer 4

unchecked exceptions.
Exceptions tend to be unexpected but not necessarily fatal

Question 5

What is checked exception?

Answer 5

Checked exceptions tend to be more anticipated—for example, trying
to read a fi le that doesn’t exist.

Question 6

java.lang.RuntimeException extends what?

Answer 6

java.lang.Exception

Question 7

What is throw?

Answer 7

tells Java that you want to
throw an Exception

Question 8

What is throws?

Answer 8

throws simply declares that the method might throw an Exception. It
also might not

Question 9

What do you pass in a throw?

Answer 9

String parameter with message or can pass no parameters
throw new Exception();
throw new Exception(“Thing”);

Question 10

What type of expection is NullPointerException

Answer 10

Run time exception

Question 11

What exception does this produce?
~~~
String[] animals = new String[0];
System.out.println(animals[0]);
~~~

Answer 11

ArrayIndexOutOfBoundsException

Question 12

What is error’s subclass of?
is the program required to declare or handle?

Answer 12

subclass of Error; No

Question 13

What is checked exception sub class of?
is the program required to declare or handle?

Answer 13

Subclass of Exception but not subclass of RuntimeException.
Yes

Question 14

What is run time exception sub class of?
is the program required to declare or handle?

Answer 14

Subclass of RuntimeException.
They don’t have to be handled or declared.
They can be thrown by the programmer or by the JVM

No.

Question 15

3: void explore() {
4: try {
5: fall();
6: System.out.println(“never get here”);
7: } catch (RuntimeException e) {
8: getUp();
9: }
10: seeAnimals();
11: }
12: void fall() { throw new RuntimeException(); }

Answer 15

fall() calls new RuntimeException and goes directly to line 7

Question 16

Does it compile?
try
fall();
catch (Exception e)
System.out.println(“get up”);

Answer 16

No because braces are missing.

Question 17

Does it compile?
try {
fall();
}

Answer 17

No because catch is missing

Question 18

catch is not
required if finally is present.

Answer 18

true

Question 19

When is finally used?

Answer 19

finally is typically used to close resources such as fi les or databases

Question 20

When does finally not get executed?

Answer 20

System.exit(0);.

Question 21

When catching exceptions if you have superclass and subclass what should you catch first?

Answer 21

subclass
then super class next.

Question 22

Why doesnt the following compile?
~~~

public void visitMonkeys() {
try {
seeAnimal();
} catch (ExhibitClosed e) { //superclass
System.out.print(“not today”);
} catch (ExhibitClosedForLunch e) {// DOES NOT COMPILE subclass
System.out.print(“try back later”);
}
}
~~~

Answer 22

Cause the super class took care of it.

Question 23

Who throws ArithmeticException?

Answer 23

RuntimeException. JVM

Question 24

Who throws ArrayIndexOutOfBoundsException?

Answer 24

JVM

Question 25

Who throws ClassCastException?

Answer 25

ClassCastException

Question 26

Who throws IllegalArgumentException?

Answer 26

programmer

Question 27

Who throws NullPointerException?

Answer 27

JVM

Question 28

Who throws NumberFormatException?

Answer 28

programmer

Question 29

What is ArithmeticException

Answer 29

divide by zero

Question 30

ArrayIndexOutOfBoundsException

Answer 30

int[] countsOfMoose = new int[3];
System.out.println(countsOfMoose[-1]);

There is no such thing as negative array index

Question 31

ClassCastException

Answer 31

Java tries to protect you from impossible casts. This code doesn’t compile because Integer
is not a subclass of String:
String type = “moose”;
Integer number = (Integer) type; // DOES NOT COMPILE

Question 32

IllegalArgumentException

Answer 32

IllegalArgumentException is a way for your program to protect itself.

Like if you dont want negative values

Question 33

NullPointerException

Answer 33

Instance Variables and methods must be called on a non-null reference. If the reference is
null, the JVM will throw a NullPointerException.
runtime

Question 34

NumberFormatException

Answer 34

trying to convert something non-numeric into an int:
Integer.parseInt(“abc”);

Question 35

FileNotFoundException

Answer 35

Checked exception. Programmer
a file does not exist

Question 36

IOException

Answer 36

problem reading or writing a file

Question 37

what is FileNotFoundException subclass of?

Answer 37

IOException

Question 38

Errors thrown by what?

Answer 38

JVM

Question 39

ExceptionInInitializerError

Answer 39

Thrown by the JVM when a static initializer throws
an exception and doesn’t handle it

Question 40

StackOverflowError

Answer 40

Thrown by the JVM when a method calls itself too many times
(this is called infi nite recursion because the method typically calls itself without end)

Question 41

NoClassDefFoundError

Answer 41

Thrown by the JVM when a class that the code uses is available
at compile time but not runtime

when Java can’t find the class at runtime

Question 42

What are checked exception?

Answer 42

Checked exceptions must be handled or declared.

Question 43

Does this compile?
~~~
class CanNotHopException extends Exception { }
class Hopper {
public void hop() { }
}
class Bunny extends Hopper {
public void hop() throws CanNotHopException { }
}
~~~

Answer 43

No bc the subclass introduced a new exception
class CanNotHopException extends Exception { }
class Hopper {
public void hop() { }
}
class Bunny extends Hopper {
public void hop() throws CanNotHopException { } // DOES NOT COMPILE
}

Question 44

System.out.println(e);

Answer 44

the exception type and message

Question 45

System.out.println(e.getMessage());

Answer 45

just the messagve

Question 46

e.printStackTrace();

Answer 46

The rest shows a stack trace

Question 47

When are you required to use a finally block in a regular try statement (not a try-withresources)?

Answer 47

when there is no clause

Question 48

Why are checked exception called checked exception?

Answer 48

Checked during the compilation.

Question 49

Checked Exception is the subclass of?
java.lang.Exception or java.lang.RuntimeException?

Answer 49

java.lang.Exception

Question 50

nmame runtime exceptions?

Answer 50

NullPointerException, ArrayIndexOutOfBoundsException, ClassCastExceptions.

Question 51

why called runtime exception?

Answer 51

it isnt feasible to determine whether a method call with throw a runtime exception until it executes.

Question 52

default value of static and instance variable

Answer 52

null