Chapter 5: Class Design

Question 1

What is inheritance?

Answer 1

The process by which the subclass automatically any public or protected primitives, objects, or methods defined in the parent class.

Question 2

If child X inherits from class Y, which in turn inherits from class Z, then what is X in relation to Z?

Answer 2

An indirect child or descendent.

Question 3

What’s the difference between single inheritance and multiple inheritances? Does Java support both?

Answer 3

Single inheritance is when the the child and parent relationship is only one level. For example, you would not be able to inherit from a grandparent in this case.

Multiple inheritance is when a class can extend multiple parents.

Java does not support multiple inheritance, but it does support single inheritance.

Question 4

Does Java support multiple levels of single inheritance? Can a child inherit from a grandparent?

Answer 4

yes

Question 5

What’s the single exception to single inheritance?

Answer 5

Interfaces, a class can implement as many interfaces as you want.

Question 6

What’s one way in java to prevent a class from being extended?

Answer 6

By marking it with the final modifier

Question 7

What’s the syntax for inheritance?

Answer 7

public class ElephantSeal extends Seal{

}

Question 8

Do children have access to private members? (fields and methods)

Answer 8

no

Question 9

Which takes up more memory? the parent or the child?

Answer 9

The child. Because the child is both the parent AND more.

Question 10

How does the default access modifier differ from the public keyword?

Answer 10

Public is available for any class to be used. Default access is only available to be used within the same package. Which differs from protected in that default access is not extended by inheritance. So a child does not have access to default access unless they parent and the child are in the same package.

Question 11

Does this compile (in the same file)?

class Rodent {}

public class Groundhog extends Rodent{}

Answer 11

Yes. Fine as only one of the classes is marked public.

Question 12

Does this compile (in the same file)?

public class Rodent {}

public class Groundhog extends Rodent{}

Answer 12

no. only one public class allowed per file.

Question 13

True or false: There can be at most one public class or interface in a Java file?

Answer 13

True

Question 14

What’s the only class in Java that doesn’t have any parent classes?

Answer 14

java.lang.Object

Question 15

Does every class have at least one constructor?

Answer 15

Yes. There is a default no-argument constructor no matter what.

Question 16

What is a super() constructor? Can it have arguments?

Answer 16

it is the constructor of any parent class. It must have arguments if the constructor has arguments.

Question 17

Will this compile? Why or why not?

public class Zoo{

public Zoo(){

System.out.println(“Zoo created”);

super();

}

}

Answer 17

No. LIke the this() command, super() must be the first statement used in a constructor.

Question 18

Will this compile? Why or why not?

public class Zoo{

public Zoo(){

super();

System.out.println(“Zoo created”);

super();

}

}

Answer 18

No. super() can only be the first statement in a constructor. It cannot be first and second, or first and third.

Question 19

If a parent has defined one constructor, is the child forced to use it?

Answer 19

yes

Question 20

if a parent has declared two constructors, does the child need to use both of the constructors?

Answer 20

No. It may use either of the declared constructors, it may use either valid constructor from the parent.

Question 21

How does Java handle the collision between parent and child classes which methods with matching signatures?

Answer 21

You can override the method, or refer explicitly to the parent version with super.() So, let’s say the child has the same method signature if you want it to do the exact same thing as the parent, just do super.(method) to get the same behavior.

Question 22

What’s the order of operations here? (Assume App2 extends App, and App3 extends App2)

public static void main(String…strings ) {

App app = new App();

App2 app2 = new App2();

App3 app3 = new App3();

}

}

Answer 22

the first line will call App’s empty constructor.

The second line will again call App’s empty constructor. then it will call App2’s version of the empty constructor.

The third line will call App’s constructor, then App2’s constructor, and then App3’s constructor.

Question 23

What are three limitations to the child being able to override a parent class? (other than, of course, the method signatures not matching)

Answer 23

1. The method int he child class must be at least as accessible or more accessible than the method in the parent class.
2. The method in the child class may not throw new exceptions or exceptions broader than the exception thrown in the parent class.
3. If the method returns a value, it must be the same or a sublclass of the method in the parent clas.

Question 24

Remember, the child method must be at least as accessible as the parent.

Question 25

What does it mean that the return type of the parent method and the child method must be covariant?

Answer 25

It means that the overridden version of the parent’s method must return something similar to the return type of the parent. So if the parent’s method returns an int, the child’s method cannot return a string.

Question 26

Anytime you see an overridden method on the exam, first check to make sure it is truly being overridden and not overloaded. After that, check the access modifiers, return types, and any exceptions defined in the method are compatible with one another.

Question 27

If the parent method has a declared exception, and the child doesn’t, will the method compile? (Assuming everything else is the same?) (overridden method)

Answer 27

Yes. As long as no new exception is defined, this isn’t a problem.

Question 28

True or fals: A child’s version of a parent’s method can hide or eliminate a parent’s method exception without issue. (overridden method)

Answer 28

True

Question 29

Is the child (overridden method) allowed to throw a more specific exception than the parent method?

Answer 29

Yes. As long as the more specific exception is a subclass of the parent’s method.

Question 30

Is a child method’s (overridden method)exception allowed to be more generic than the parent’s exception declaration?

Answer 30

No. It can only go from less specific to more specific, from the top down.

Question 31

Can a child’s overridden version of a parent’s method declare a method exception when the parent’s does not?

Answer 31

No.

Question 32

Is it possible for a child class to override a private method from it’s parent?

Answer 32

No. Private methods and fields or only accessible within the class.

Question 33

What’s the difference between an overridden method and a hidden method?

Answer 33

Essentially the only difference is that because it’s static you don’t need to use the @Override annotation. The method is bound to the class, not an object. So as far as the parent/child knows, it isn’t really there.

Question 34

What happens if you attempt to hide a method on a child, but the method isn’t marked static on both the parent and the child?

Answer 34

Will not compile. At that point, you need to make both methods static to hide it, or non static and override it.

Question 35

Can you override a method if it is marked final?

Answer 35

No. Final methods cannot be overridden.

Question 36

Can you override a hidden method if it has been marked final?

Answer 36

No.

Question 37

Can you mark an overridden version of a parent’s method final on the child?

Answer 37

Yes. But if the parent is marked final you cannot override the method at all.

Question 38

Why is it important to not that app2 build’s it’s own copy of app, and that app3 build it’s own copy of app2 and app, that are not the same as the copy made by app2?

public static void main(String…strings ) {

App app = new App(10);

App2 app2 = new App2(11);

App3 app3 = new App3(12);

System.out.println(“App’s number “ + app.number);

//prints it’s own number as well as it’s super’s number

app2. printNumbers();
app3. printNumbers();

}

}

Answer 38

It’s important to note because if you are making calls to get information from the super, you need to know that not one ur-super is made per program, that each child talks to. If you want fields or methods that are available, like an urtext, you need to make them static.

Question 39

What 2 goals might make you want to provide an abstract class?

Answer 39

1. You want to provide reusable methods and classes to developers in the parent class, yet force them to provide their own implementations.
2. You don’t ever want someone to make an instance of that class, unless its a child.

Question 40

What is an abstract class?

Answer 40

It’s a class marked with the abstract keyword that can’t be instantiated.

Question 41

Can you have abstract methods on a non abstract class?

Answer 41

no

Question 42

Will this compile?

public abstract class TestAbstract {

abstract public void printStuffMethod() {};

}

Answer 42

No. Abstract methods cannot have a method body as defined by the curly brackets.

Question 43

Can you have non abstract methods on an abstract class?

Answer 43

Yes.

Question 44

Can you have non abstract fields on an abstract class?

Answer 44

Yes

Question 45

Can you have abstract methods inside a non abstract class?

Answer 45

no

Question 46

Can you have abstract variables, methods, and classes?

Answer 46

No, you cannot have abstract variables. But you can have abstract methods and classes

Question 47

Which of these wont compile:

public abstract class TestAbstract {

(1) public abstract int stuff;
(2) public int moreStuff;
(3) public void printStuffMethod() {};
(4) public abstract void printMoreStuffMethod() {};
(5) public void printEvenMoreStuff();
(6) public abstract void printEvenEvenMoreStuff();

}

Answer 47

1 won’t work because you can’t have an abstract field.

2. this is just fine.

3 this is just fine

4 won’t work because abstract methods cant have a body

5 won’t work because it doesn’t have a body

6 this is fine

Question 48

Does this compile?

public abstract class TestAbstract {

public int moreStuff;

public void printStuffMethod() {System.out.println(“in the abstract class”);};

public abstract void printMoreStuffMethod();

public abstract void printEvenEvenMoreStuff();

}

Answer 48

Yes. The int is fine because it’s not abstract. The method with a body is fine because its not abstract. The other abstract methods work because they don’t have a body.

Question 49

Will this compile?

public abstract class whale{

protected abstract void sing();}

public class HumpbackWhale extends Whale{

private void sing(){System.out.println(“Humpback whale sings”);}

}

Answer 49

No. You cannot reduce the accessibility of a super’s method. In the super the method is protected, but in the child it is private.

Question 50

When does an abstract class become useful?

Answer 50

When it is extended by a concrete subclass.

Question 51

Does this compile?

public abstract class Animal{

public abstract String getName();}

public class Bird extends Animal{}

Answer 51

No. The first concrete class of an abstract subclass must implement the supers methods.

Question 52

Why doesn’t this compile?

public abstract class Animal{

public abstract String getName();}

public class Walrus extends Animal{}

public abstract class Eagle extends Aniaml{}

Answer 52

This fails to compile because as Walrus is not abstract, and it is a first order descendent, it must implement the abstract methods of the parent. Because Eagle is abstract it compiles just fine.

Question 53

Are abstract classes allowed to extend other abstract classes without implementing the super’s methods?

Answer 53

yes.

Question 54

If an intermediate class (abstract OR concrete) provides an implementation for an abstract method, is that method inherited as a concrete method, or an abstract one? Does it matter whether or not the class providing the implementation is concrete or abstract?

Answer 54

It is inherited as a concrete method. It doesn’t matter whether the implementation comes from an abstract or concrete intermediary.

Question 55

Assuming a concrete class extends this class, and that it is the first concrete class to extend it, which of the following methods must be implemented on the concrete child?

public abstract class TestAbstract {

public int moreStuff;

public void printStuffMethod() {System.out.println(“in the abstract class”);};

public abstract void printMoreStuffMethod();

public abstract void printEvenEvenMoreStuff();

}

Answer 55

All but the printStuffMethod(). As it already has an implementation, the child doesn’t need to provide a new one.

Question 56

If this class were extended by an abstract class, which of the following methods would need to be overridden?

public abstract class TestAbstract {

public int moreStuff;

public void printStuffMethod() {System.out.println(“in the abstract class”);};

public abstract void printMoreStuffMethod();

public abstract void printEvenEvenMoreStuff();

}

Answer 56

None. Abstract classes don’t really have to do anything with the methods on their abstract super.

Question 57

How many methods does the class Lion need to implement?

public abstract class Animal{public abstract String getName();}

public abstract class BigCat extends Animal{public abstract void roar();}

public class Lion extends BigCat{}

Answer 57

Two. Because no implementation has previously been provided by the parent and the grandparent, Lion must do both.

Question 58

Why doesn’t this compile?

abstract class Test2{

public abstract void printMoreStuff() {};

}

Answer 58

Can’t have a body {} on an abstract method.

Question 59

Does this compile?

public class Main extends Test3 {

public static void main(String[] args) {

}

}

abstract class Test1{

public void printStuff() {System.out.println(“shiz”);}

}

abstract class Test2{

public abstract void printMoreStuff();

}

class Test3 extends Test2{

@Override

public void printMoreStuff() {

System.out.println(“Print More Stuff”);

}

}

Answer 59

yes

Question 60

Why doesn’t this comopile?

public class Main extends Test3 {

public static void main(String[] args) {

}

}

abstract class Test1{

public void printStuff() {System.out.println(“shiz”);}

}

abstract class Test2{

public abstract void printMoreStuff();

}

class Test3 extends Test2{

}

Answer 60

Test 3 needs to implement printMoreStuff();

Question 61

Why doesn’t this compile?

String name = “Jedd”;

switch (name){

case “Jedd”: System.out.println(“Name is equal to Jedd”);

case “Kade”: System.out.println(“Name is equal to Kade”);

case “Ben”: System.out.println(“Name is equal to Ben”);

case new String(“Tracy”) : System.out.println(“name is equal to Tracy”);

}

Answer 61

Case expressions must be constant expressions. So the ‘new’ keyword cant be used.

Question 62

What is the output?

int x = 1;

switch (x){

case 1: System.out.println(“x is equal to one”);

case 2: System.out.println(“x is equal to 2”);

case 3: System.out.println(“x is equal to three”);

default: System.out.println(“none of these”);

}

Answer 62

as there is no break statement, everything after case 1, the case that returned true, will run.

Question 63

What is the output?

int x = 5;

switch (x){

case 1: System.out.println(“x is equal to one”);

break;

case 2: System.out.println(“x is equal to 2”);

break;

case 3: System.out.println(“x is equal to three”);

break;

default: System.out.println(“none of these”);

case 4: System.out.println(“x is equal to 4”);

}

Answer 63

The default and case 4 will print out. Case 4 would not print out, however, if the default statement were followed by a break; statement.

Question 64

Can you use a continue statement inside of a switch statment?

Answer 64

Yes. But it must be within a for loop of sorts.

Question 65

can you make a List<t> of primitives? </t>

Answer 65

no, List<> can only work with objects.

Question 66

what is the output:

char y = ‘y’;

char z = ‘z’;

List<integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7);</integer>

switch (y) {

case ‘y’:

for (int i = 0; i < numbers.size(); i++) {

System.out.println(“y is equal to y”);

break;

}

break;

case ‘z’:

System.out.println(“y is equal to z”);

default:

System.out.println(“y isn’t equal to anything”);

}

}

Answer 66

y is equal to y

Question 67

what is the output?

char y = ‘y’;

char z = ‘z’;

List<integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7);</integer>

switch (y) {

case ‘y’:

for (int i = 0; i < numbers.size(); i++) {

System.out.println(“y is equal to y”);

continue;

}

break;

case ‘z’:

System.out.println(“y is equal to z”);

default:

System.out.println(“y isn’t equal to anything”);

}

Answer 67

y is equal to y

y is equal to y

y is equal to y

y is equal to y

y is equal to y

y is equal to y

y is equal to y

Question 68

Can you instantiate an abstract class directly?

Answer 68

No.

Question 69

How many abstract and/or non abstract methods can be defined on an abstract class?

Answer 69

As many as you want! Even zero

Question 70

Can abstract classes be marked private, protected, or final?

Answer 70

NO

Question 71

What happens to the abstract methods of an abstract class when it is extended by another abstract class?

Answer 71

It inherits all of the abstract methods as their own. So when the abstract child is extended by a concrete class, those methods are passed on even though they need not be defined on the abstract child.

Question 72

What must the first concrete class which inherits abstract methods from an abstract parent?

Answer 72

Implement the abstract methods. Remember, however, that if the methods are not abstract and, therefore, have definitions, the concrete child doesn’t have to do anything with those already implemented methods.

Question 73

Can you define an abstract method on a non-abstract class?

Answer 73

no

Question 74

Can you declare abstract methods as private or final?

Answer 74

no

Question 75

Can abstract methods have a body {}?

Answer 75

no

Question 76

Is implementing an abstract method similar to overriding, in that the method signatures must match?

Answer 76

yes

Question 77

How accessible does an implementation of an abstract method, or an overridden method, need to be?

Answer 77

At least as accessible as the method when it is first declared.

Question 78

How many interfaces is a class allowed to implement?

Answer 78

Any number.

Question 79

What is an interface?

Answer 79

An abstract data type that defines a list of abstract public methods that any class implementing the interface must provide.

Question 80

Are interfaces allowed to include a list of constant variables and default methods?

Answer 80

yes

Question 81

Why doesn’t this compile?

public interface TestInterface1 {

public int one = 1;

static int two = 2;

final int three = 3;

protected int four = 4;

}

Answer 81

only public, static, and final modifiers are allowed for interface constants.

Question 82

Why doesn’t this compile?

public interface TestInterface1 {

public int one = 1;

static int two = 2;

final int three = 3;

public int four = one + 4;

public String name = “Jedd”;

public abstract int getNumberOne();

public int getNumberFour() {return this.four};

public default int getNumberTwo() {return TestInterface1.two;}

public default int getNumberThree() {return three;}

public static int getNumbers() {return one;}

}

Answer 82

The methods of an interface must have either static or default in the signature. Otherwise it wont compile. The rest are fine.

Question 83

What part of an interface signature is assumed (not shown) in this example?

public interface Whatever{}

Answer 83

The abstract keyword.

Question 84

Will this compile?

protected abstract interface Whatever{}

Answer 84

No. Protected is not allowed. All interfaces must be public.

Question 85

Will this compile as the declaration of an interface?

interface Whatever{}

Answer 85

Yes. Public and abstract are both assumed for all interfaces.

Question 86

What’s the proper way to define multiple implementations of interfaces on a concrete class?

Answer 86

public class Elephent implmements Interface1, Interface2, Interface3 and so on.

Question 87

Can interfaces be instantiated directly?

Answer 87

no

Question 88

Is an interface required to have any methods or fields?

Answer 88

no

Question 89

Can an interface be marked as final?

Answer 89

no

Question 90

Can an interface be marked as private?

Answer 90

no

Question 91

What access is assumed for an interface?

Answer 91

public or default?

Question 92

What level of concreteness is assumed for an interface?

Answer 92

abstract

Question 93

Will making an interface private, protected, or final trigger a compiler error?

Answer 93

yes. But only if it’s a top level interface.

Question 94

Which two method signature modifiers are all non-default methods on an interface assumed to have?

Answer 94

public abstract

Question 95

What happens if you mark a method on an interface protected, private, or final?

Answer 95

This will trigger a compiler error.

Question 96

Which asssumed keywords are we not seeing?

public interface Whatever{

void fly(int speed);

abstract void takeOff();

public abstract double dive();

Answer 96

public and abstract will be added to each method by the compiler.

Question 97

Why doesn’t any of this compile?

private final interface CanCrawl{

private void dig(int depth);

protected abstract double depth();

public final void surface();

}

Answer 97

can’t mark an interface final or private.

cant mark a interface method private

can’t mark an interface method protected

can’t mark an interface method final

Question 98

Which of the methods from this interface will need to be implemented by concrete class?

public interface TestInterface1 {

public int one = 1;

static int two = 2;

final int three = 3;

public int four = one + 4;

public String name = “Jedd”;

public abstract int getNumberOne();

public default int getNumberTwo() {return TestInterface1.two;}

public default int getNumberThree() {return three;}

public static int getNumbers() {return one;}

}

Answer 98

Only getNumberOne(); The others are default or static.

Question 99

An interface that extends another interface, as well as an abstract class that implements an interface, ____ all of the abstract methods as its own abstract methods.

Answer 99

inherits

Question 100

Does an interface implement another interface or extend it?

Answer 100

Extend

Question 101

Does this compile?

public interface TestInterface3 extends TestInterface1, TestInterface2 {

}

Answer 101

yes

Question 102

Can abstract classes extend multiple other abstract classes?

Answer 102

no

Question 103

Can an interface extend more than one other interface? Why would you do that?

Answer 103

yes. To pass along the abstract methods to the child.

Question 104

The first concrete class that implements an interface, or extends an abstract class that implements an interface, must _____

Answer 104

provide an implementation for all of the inherited abstract methods

Question 105

What happens when an abstract class implements an interface?

Answer 105

The abstract class inherits the interface’s abstract methods but is not required to implement them.

Question 106

Can a class extend an interface?

Answer 106

no

Question 107

Will this compile?

public class Hello extends [interface]{

}

Answer 107

No. Only

Question 108

Finish this sentence: class ____ interface {}

Answer 108

implements

Question 109

Fill in the blank: interface ____ interface

Answer 109

extends

Question 110

What happens if a class implements two interfaces, each of which has a method with the same signatures as that on the other interface? Will there be a collision when they are defined by the concrete class?

Answer 110

No. you only have to provide one implementation and it will count for both.

Question 111

What happens when a concrete class implements two interfaces, each of which has methods of the same name with albeit different method signatures? Is the concrete class forced to provide to implementations, one for each method signature?

Answer 111

Yes. You must provide an implementation for each method signature override.

Question 112

Is it possible in Java to define two methods in a class with the same name and input parameters but different return types? Why could this present a problem if the same method name has different return types, implemented from two different interfaces?

Answer 112

no. This is a porblem because you may think you are overriding a method, but you aren’t. The method name is the same but the signatures are not the same.

Question 113

Interface variables are assumed to be ____, _____, and _____

Answer 113

public, static and final

Question 114

The ____ of an interface variable must be ____ when it is declared since it is marked as _____ implicitly.

Answer 114

value, set, final

Question 115

What is a default method?

Answer 115

A method defined within an interface with the default keyword in which a method body is provided

Question 116

What’s the difference between an interface’s default method and it’s other “regular” methods?

Answer 116

The default can provide an implementation, which means it is not abstract.

Question 117

Are classes required to override an interfaces default method?

Answer 117

No. But they can if they want to

Question 118

Can a default method be declared in an abstract or concrete class?

Answer 118

No. Only in interfaces

Question 119

Must the default method be marked with the default keyword?

Answer 119

yes

Question 120

Can a method marked default not provide a body?

Answer 120

no

Question 121

Is a default method assumed to be static, final, and abstract?

Answer 121

No. This is clear as it can be overridden by another class.

Question 122

Like all methods in an interface, a default method is assumed to be _____ and will not compile if marked as private or protected

Answer 122

public

Question 123

The type of the object determines which _____ exist within the object in memory.

Answer 123

properties

Question 124

The type of the ______ to the object determines which methods and variables are accessible to the Java program.

Answer 124

reference

Question 125

Why doesn’t this compile?

public class Main {

public static void main(Strings…strings) {

Harold harold = new Harold();

System.out.println(harold.getName());

Object object = harold;

System.out.println(object.getName());

}

}

class Harold{

protected String name = “Harold” ;

protected int age = 55;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

}

Answer 125

Because once the reference object takes over the reference harold pointing at the Harold object, harold becomes only that which Object has the power to do.

Question 126

What is the output?

public class Main {

public static void main(String…strings) {

Harold harold = new Harold();

Object objectHarold = harold;

Harold harold2 = (Harold) objectHarold;

harold2.setName(“ChangedName”);

System.out.println(objectHarold);

System.out.println(harold);

System.out.println(harold==objectHarold);

System.out.println(harold==harold2);

}

}

class Harold{

protected String name = “Harold” ;

protected int age = 55;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

@Override

public String toString() {

return getName();

}

}

Answer 126

ChangedName

ChangedName

true

true

Question 127

Does casting an object from a subclass to a superclass require an explicit cast?

Answer 127

no

Question 128

Does casting an object from a superclass to a subclass require an explicit cast?

Answer 128

yes

Question 129

Will the compiler allow casts to unrelated types?

Answer 129

no

Question 130

When casting an object type, is it possible for the code to compile without throwing an error during compile time, yet have an exception be thrown at runtime? If yes, why?

Answer 130

Yes. The error will be thrown at runtime of the object being cast is not actually an instance of that class.

Question 131

What is a virtual method?

Answer 131

a method in which the specific implementation is not determined until run time.

Question 132

In fact, all non-final, non-static, and non-private methods are considered ____ methods, since any of them can be overridden at runtime.

Answer 132

Virtual method

Question 133

What is the output? And what is the principle demonstrated (hint: virtual methods)

public class Main {

public static void main(String… strings) {

Bird bird = new Peacock();

bird.displayInfo();

}

}

class Bird {

public String getName() {

return “Unknown”;

}

public void displayInfo() {

System.out.println(“The bird name is “ + getName());

}

}

class Peacock extends Bird{

public String getName() {

return “Peacock”;

}

}

Answer 133

The bird name is Peacock

Even though the Bird class defines a method getName(), a class extending Birdclass redefines a method of the same name, which returns a different String. This does not occur until runtime (aka when an instance of Peacock is created the method on the parent is redefined).

Question 134

Explain a polymorphic parameter

Answer 134

A polymorphic parameter refers to the ability of subclasses to be passed as parameters to a method when the parameter defined is that of the super class. Because the superclass is the parameter type, you can pass in a subclass of the super as a parameter.

Question 135

What is an exception?

Answer 135

Java’s way of saying i give up. I don’t know what to do, you need to fix something.

Question 136

What do exceptions fundamentally do?

Answer 136

Interrupt program flow

Question 137

Java has a ____ exception superclass for all objects.

Answer 137

Throwable

Question 138

What are three subclasses of throwable?

java. lang._______
java. lang.________

(child of the preceding exception class)

java.lang_______

Answer 138

java. lang.Error
java. lang.Exception
java. lang.RuntimeException