Review

Question 1

What type does the Integer.parseInt method return?

Answer 1

Primitive integer (int)

Question 2

What type does the Integer.valueOf method return?

Answer 2

Integer object

Question 3

What does the ArrayList set( ) method do?

Answer 3

Sets an element at the index provided to the value provided

Question 4

In Java, forward references to local variables are not allowed.

Answer 4

True

Question 5

If a variable is declared in a switch statement case, it is available to all cases after it, but not before it.

Answer 5

True

Question 6

Only a String, byte, short, int or char can be used as types of a switch variable.

Answer 6

False, the wrapper classes of these primitives can also be used.

Question 7

You can start a literal value with an underscore.

Answer 7

False

Question 8

A literal is a fixed value that doesn’t need further calculations in order for it to be assigned to any variable.

Answer 8

True

Question 9

The char data type can be assigned a positive or a negative integer.

Answer 9

False, char is unsigned, it can only be assigned a positive integer value.

Question 10

A top level class cannot be defined with the private or protected access modifier.

Answer 10

True

Question 11

A concrete class cannot define an abstract method.

Answer 11

True

Question 12

Local variables can be defined with access modifiers.

Answer 12

False

Question 13

The append( ) method adds a String to the end of a String object.

Answer 13

False, the append( ) method belongs to StringBuilder.

Question 14

Variables local to an if block are accessible to any else if or else blocks that follow it as well.

Answer 14

False

Question 15

static public final void jump( ) { } is a valid method.

Answer 15

True

Question 16

String static public jump( ) is a valid method

Answer 16

False, the return type is out of place.

Question 17

public static void 2test ( ) { } is a valid method

Answer 17

False, you cannot start an identifier with a number.

Question 18

Method arguments are the variables that appear in the definition of a method.

Answer 18

False, method arguments are the actual values that are passed to a method.

Question 19

Static methods can access the nonstatic variables and methods of a class.

Answer 19

False.

Question 20

To import the static method sort( ) from the Collections class, you would use the statement import static java.util.Collections;

Answer 20

False, static imports are only able to import static members, so import static java.util.Collections.*; or import static java.util.Collections.sort would be valid.

Question 21

When a constructor is given the private access modifier, the class cannot be instantiated except for within itself.

Answer 21

True

Question 22

When calling this( ) in a constructor, it can be placed anywhere in the constructor.

Answer 22

False, this( ) must be the first statement in any constructor that is calling it.

Question 23

Java supports multiple inheritance of type, but not multiple inheritance of state.

Answer 23

True

Question 24

The Java compiler will not ignore extra semicolons.

Answer 24

False, it does ignore extra semicolons.

Question 25

In Java, autoboxing/unboxing is preferred over widening a variable.

Answer 25

False, widening is preferred over autoboxing/unboxing.

Question 26

The order of initialization in a Java class is static variables/initializers, superclass, constructor, then instance variables/initializers.

Answer 26

False, the order of initialization is superclass, static variables/initializers, instance variables/initializers, and constructors.

Question 27

Abstract methods cannot be declared private or final.

Answer 27

True.

Question 28

Abstract methods can be defined in concrete classes.

Answer 28

False, abstract methods can only be defined in abstract classes.

Question 29

An abstract method can be defined as static.

Answer 29

False, abstract methods cannot be defined as static.

Question 30

Variables in an interface are implicitly public, static and final.

Answer 30

True.

Question 31

Methods in an interface are implicity abstract and public.

Answer 31

True.

Question 32

An interface method cannot be static.

Answer 32

False, it can be static as long as it has a body.

Question 33

An interface method cannot be defined as protected.

Answer 33

True.

Question 34

An interface method can be declared as private as long as the method has a body.

Answer 34

True.

Question 35

Interfaces inherit from java.lang.Object.

Answer 35

False, only classes inherit java.lang.Object.

Question 36

A method defined with the final modifier can be overridden as long as the method has the same parameters.

Answer 36

False, final methods cannot be overridden.

Question 37

Checked exceptions are subclasses of the Exception class.

Answer 37

True.

Question 38

You are required to handle Unchecked Exceptions.

Answer 38

False

Question 39

Throwable is a subclass of the Exception class.

Answer 39

False, it is a super class of Exception.

Question 40

IOException is a subclass of …

Answer 40

Exception

Question 41

SecurityException is a subclass of …

Answer 41

RuntimeException

Question 42

ClassCastException is a subclass of …

Answer 42

RuntimeException

Question 43

NullPointerException is a subclass of …

Answer 43

RuntimeException

Question 44

IndexOutOfBoundsException is a subclass of …

Answer 44

RuntimeException

Question 45

You can override a parent class static method with a non-static method of the same name and parameters in its subclass.

Answer 45

False, you cannot override a static method with a non static method, and vice versa.

Question 46

Variables can be defined as abstract.

Answer 46

False

Question 47

You can concatenate a char with a String without casting.

Answer 47

True

Question 48

The wrapper classes of the primitive data types are mutable.

Answer 48

False, they are immutable, but using operators on them that change them, like ++ or –, will return an object with the new value to the reference.

Question 49

All interface variables are considered public, static, and final, even if not declared as such.

Answer 49

True.

Question 50

The compiler checks the validity of a call on a reference variable by looking at the declared class of that reference.

Answer 50

True.