1- Jcp Test: Declaration And Access Control

Front 1

Which are true? (Choose all that apply.)

A. "X extends Y" is correct if and only if X is a class and Y is an interface.

B. "X extends Y" is correct if and only if X is an interface and Y is a class.

C. "X extends Y" is correct if X and Y are either both classes or both interfaces.

D. "X extends Y" is correct for all combinations of X and Y being classes and/or interfaces.

Back 1

C is correct

A is incorrect because classes implement interfaces, they don't extend them.

B is incorrectbecause interfaces only "inherit from" other interfaces.

D is incorrect based on the precedingrules.

Front 2

"static imports," the syntax is import static…

Back 2

true

Ex: import static org.hamcrest.Matchers.hasProperty;

Front 3

A source code file can have more than one public class.

Back 3

false

A source code file can have only one public class.

Front 4

Files with no public classes have no naming restrictions.

Back 4

True

Files with no public classes have no naming restrictions.

Front 5

Classes can also be modified only with final, abstract

Back 5

False

Classes can also be modified only with final, abstract, or strictfp

Front 6

A single abstract method in a class doesn't mean the whole class must beabstract.

Back 6

False

A single abstract method in a class means the whole class must beabstract.

Front 7

The first concrete class to extend an abstract class must implement all of itsabstract methods

Back 7

True

The first concrete class to extend an abstract class must implement all of itsabstract methods

Front 8

Interfaces are contracts for what a class can do, but they say nothing aboutthe way in which the class must do it

Back 8

True

Interfaces are contracts for what a class can do, but they say nothing aboutthe way in which the class must do it

Front 9

Interface constant declarations of public, static, and final are optionalin any combination

Back 9

True

Interface constant declarations of public, static, and final are optionalin any combination

Front 10

A legal nonabstract implementing class has the following properties:

It could declare any new checked exceptions for an implementationmethod.

Back 10

False

It must not declare any new checked exceptions for an implementationmethod.

Front 11

A legal nonabstract implementing class has the following properties:

It must not declare any checked exceptions that are broader than theexceptions declared in the interface method.

Back 11

True

It must not declare any checked exceptions that are broader than theexceptions declared in the interface method.

Front 12

A legal nonabstract implementing class has the following properties:

It may declare runtime exceptions on any interface methodimplementation regardless of the interface declaration.

Back 12

True

It may declare runtime exceptions on any interface methodimplementation regardless of the interface declaration.

Front 13

A legal nonabstract implementing class has the following properties:

It must maintain the exact signature (allowing for covariant returns) andreturn type of the methods it implements (but does not have to declarethe exceptions of the interface).

Back 13

True

Front 14

If a class cannot be accessed, its members can be accessed.

Back 14

False

If a class cannot be accessed, its members cannot be accessed.

Front 15

protected members can be accessed only by subclasses regardless of package

Back 15

False

protected members can be accessed by other classes in the samepackage, plus subclasses regardless of package

Front 16

protected = package + kids (kids meaning subclasses)

Back 16

True

protected = package + kids (kids meaning subclasses)

Front 17

A protected member inherited by a subclass from another package isnot accessible to any other class in the subclass package, except for thesubclass' own subclasses.

Back 17

True

A protected member inherited by a subclass from another package isnot accessible to any other class in the subclass package, except for thesubclass' own subclasses.

Front 18

Local variables have default values

Back 18

False

Local variables don't get default values, so they must be initialized before use

Front 19

abstract methods end in a semicolon—no curly braces.

Back 19

True

abstract methods end in a semicolon—no curly braces.

Front 20

The synchronized modifier applies only to methods and code blocks.

Back 20

True

The synchronized modifier applies only to methods and code blocks.

Front 21

The strictfp modifier applies only to classes.

Back 21

False

The strictfp modifier applies only to classes and methods.

Front 22

abstract methods cannot be protected.

Back 22

False

abstract methods must be implemented by a subclass, so they must beinheritable. For that reason:

❑ abstract methods cannot be private.

❑ abstract methods cannot be final

Front 23

In methods with normal parameters and a var-arg, the var-arg must come last

Back 23

True

In methods with normal parameters and a var-arg, the var-arg must come last

Front 24

A var-arg method can have multiple var-arg parameters.

Back 24

False

A var-arg method can have only one var-arg parameter.

Front 25

Instance variables can

❑ Have any access control

❑ Be marked final or transient

Back 25

True

Instance variables can

❑ Have any access control

❑ Be marked final

Front 26

Instance variables can be abstract, synchronized, native, or strictfp.

Back 26

False

Instance variables can't be abstract, synchronized, native, or strictfp.

Front 27

final variables can be reassigned once assigned a value.

Back 27

False

final variables cannot be reassigned once assigned a value.

Front 28

final variables must be initialized before the constructor completes

Back 28

True

final variables must be initialized before the constructor completes

Front 29

An object reference markedfinal does NOT mean the object itself can't change

Back 29

True

An object reference markedfinal does NOT mean the object itself can't change

Front 30

The transient modifier applies only to instance variables.

Back 30

True

The transient modifier applies only to instance variables.

Front 31

The volatile modifier applies only to instance variables.

Back 31

True

The volatile modifier applies only to instance variables.

Front 32

When you declare an array, the brackets can be to the left or to the right ofthe variable name

Back 32

True

When you declare an array, the brackets can be to the left or to the right ofthe variable name

Front 33

An array of objects can hold any object that passes the IS-A (orinstanceof) test for the declared type of the array. For example, if Horseextends Animal, then a Horse object can go into an Animal array.

Back 33

True

An array of objects can hold any object that passes the IS-A (orinstanceof) test for the declared type of the array. For example, if Horseextends Animal, then a Horse object can go into an Animal array.

Front 34

An enum can be declared outside or inside a class and in a method

Back 34

False

An enum can be declared outside or inside a class, but NOT in a method

Front 35

An enum declared outside a class must could be marked static, final,abstract, protected, or private

Back 35

False

An enum declared outside a class must NOT be marked static, final,abstract, protected, or private

Front 36

enum constructors can NEVER be invoked directly in code. They are alwayscalled automatically when an enum is initialized.

Back 36

True

enum constructors can NEVER be invoked directly in code. They are alwayscalled automatically when an enum is initialized.

Front 37

The semicolon at the end of an enum declaration is mandatory

Back 37

False

The semicolon at the end of an enum declaration is optional

Front 38

MyEnum.values() returns an array of MyEnum's values

Back 38

True

MyEnum.values() returns an array of MyEnum's values