Data Structures Drill 1

What is the difference between a local variable and a field?

A local variable is declared in the body of a method and can be used only from the point at which it's declared through the end of the method declaration. A field is declared in a class, but not in the body of any of the class's methods. Also, fields are accessible to all methods of the class (with one exception: static fields are not accessible to non-static methods).

Method overriding

A method of the same name and argument list as a method in a parent class, so it replaces the parent method.

ClassCastException

An exception thrown when an object variable is cast with an incompatible class. 2.6: when code tries to downcast a tree to a Redwood an exception error is thrown at runtime

one way to make code reusable is to _________ or by combining data elements together with methods that operate on that data in a separate program module

Encapsulate

An interface is a class (True/False)

False

An array can store many different types of values (True/False)

False arrays can only store values of the same type

the nextInt( ) method throws this error if an integer choice is not entered

InputMismatchException

Method overloading (2)

It's possible to have several methods with the same name that each operate on different types or numbers of arguments. This feature is called method _______.

To String( ) Method

Java automatically applies this to an object referenced in a String expression

the nextInt( ) method will throw this exception when a program attempts to convert a non-numeric string to a numeric value

NumberFormatException

The superclass of all Java classes

Object

ArrayIndexOutOfBoundsException

Thrown to indicate that an array has been accessed with an illegal index. The index is either negative or greater than or equal to the size of the array.

What method should you always override if you want to represent an object's state?

To String( )

A major reason for the popularity of object-oriented programming is that it enables programmers to reuse previously written code saved as classes (True/False)

True

Each class that implements an interface must provide the complete definition of all methods declared in the interface (True/False)

True

Protected Visibility

a data field or method with this can be accessed in either the class defining it, in any subclass of that class, or any class in the same package

Contract

a java interface bridges this connection between the interface designer and the programmer who codes a class that implements the interface

Abstraction

a model of a physical entity or activity

The has-a relationship

between classes means that one class has the second class as an attribute

The is-a relationship

between classes means that one class is a subclass of the other

Which method of java.lang.Object compares an object to its argument?

boolean equals(Object obj)

This( )

call invokes the constructor for the current class whose parameter list matches the argument list

A class's public interface

consists of the class's public member functions

If a class declares constructors, the compiler will NOT create a _________

default

Method overloading

having multiple methods with the same name but different signatures in a class

No parameter Constructor

if no constructors are defined for a class this constructor will be provided by default

The Super call

in a class constructor invokes the superclass's constructor that has the corresponding argument list

Private visibility

is for members of a class that should not be accessible to anyone but the class, not even classes that extend it

Wrapper class

is used to store a primitive-type value in an object type

method declaration

method descriptions in an interface

Runtime error

occurs during program execution

Which of the following is considered a visibility modifier in Java? private inherit superclass string

private

what members do classes that are not part of a package have access to?

public members

Static variable

represents class wide information that's shared by all the objects of the class

Keyword new

requests memory from the system to store an object, then calls the corresponding class's constructor to initialize the object

If a method contains a local variable with the same name as one of its class's fields, the local variable _______ the field in that method's scope.

shadows

Java Interface

specifies the names, parameters, and return values of the ADT methods without specifying how the methods perform their operations or how the data is internally represented

abstract data type

the combination of data together with its methods