COMP1210 Test 1 (Cross)

x and y are variables that refer to the same object

If x and y are aliases of each other with respect to reference types in Java, then

semantics

"meaning"; what a given legal structure in the language means

local data

(declared inside of a method); can only be used within that method

instance data

(fields declared at the top of the class); can be referenced by all methods in that class

support, service

A private method is referred to as a ________ method, while a public method is referred to as a _______ method.

string literal

A string of characters can be represented as a _________ by putting double quotes around the text.

scope

A variable's _______ is determined by where it is declared.

instance

An object is an _____ of some particular class.

the main method of your class

Executed first when you run your Java application

2^10

How many unique items can be represented by 10 bits?

instance variables, methods

In object oriented programming, the ______ of the class define the state of an object (or instance) of the class, whereas the _________ of the class define the behavior of an object (or instance) of the class.

private

Instance variables should be declared with what type of visibility to promote encapsulation?

strongly typed

Java is __________, so in an assignment statement, the type of the variable on the left and the type of the result of the expression on the right must be compatible

true

Java is a high-level, compiled, object oriented programming language.

false

Java is interpreted, but not compiled.

Sun Microsystems

Java was developed by ______.

inheritance

New classes are derived from existing ones through ________.

programming language

Specifies the words and symbols that we can use to write a program

private, public

Well encapsulated classes have _____ variables and _______ methods.

instance data

When an object is created, spaced is reserved in memory for that object's _______.

False

when the new operator creates an object, a destructor with the same name as the class is invoked to help set it up initially

java.lang

Which Java Class Library is imported automatically?

Java bytecode, Java source code

______ is created by the Java compiler based on the ________.`

mutator, state

_______ method changes the _______ of the object

false

a private method can be invoked outside the class since it helps the other methods of the class do their job

aliases

when two or more references refer to the same object

true

a string object is immutable meaning the object cannot be changed in memory once it has been created

reserved

word in programming languages that is set aside for special purposes

if statement

allows a program to execute a statement or block {} only under certain conditions

if-else statement

allows a program to execute one statement or block {} for a true condition and a different statement or block {} for a false condition

character set

an ordered list of characters, and character represents a unique number

autoboxing

automatic conversion of a primitive value to a corresponding wrapper object

method header

begins method declaration with formal parameters

mutator method

changes the value of a variable; "setter"

UML

class diagrams that show relationships among classes in the program

NumberFormat

class that formats values as currency or percentages

DecimalFormat

class that formats values based on a pattern

Wrapper

class that provides the object equivalent of a primitive type

compile-time errors

compilation cannot be completed because of syntax errors or static semantic errors

arithmetic expressions

compute numeric results and make use of arithmetic operators

expression

construct made up of one or more variables, operators, and method invocations that evaluates to a single value

class

contains zero or more data and/or methods

method

contains zero or more local data and/or program statements that form an algorithm

actual parameters

copied into the formal parameters when the method is called

instantiation

creating an object

support methods

declared as private and can only be used by other methods in the class

access modifiers

define who can access an instance variable or method

reference variables

don't hold the object, but hold a memory location where the object is stored

scope

enclosing context in a program where that data can be referenced

assignment statement

example: myVar = 7;

escape sequences

examples: \t, \\, \", \n

run-time errors

execution is halted abnormally (deep end, crash, blow up, crash and burn)

logical errors

execution proceeds and halts normally, but incorrect behavior or incorrect results are observed

method body

follows the method header; created each time the method is called, and is destroyed with it finishes executing

widening conversions

go from a smaller to larger data type

narrowing conversions

go from large data type to a smaller one; you may lose data

algorithm

implemente by the instructions in the methods of a program

byte, short, int, long

increasing range of values for integer types

return type

indicates the type of value that the method sends back to the calling location

IDE (integrated development environment)

jGRASP is an example of an ________

program

made up of one or more classes

public

members of a class can be referenced anywhere

private

members of a class can only be referenced within that class

static

modifier allows it to be shard among all methods in the class

final

modifier prevents the initial value from changing

variable

name for a "location" in memory that holds program data

String

not a primitive type in Java

encapsulation

object thought of as a "black box"; its inner workings are hidden from the client

8

one byte has ___ bits

new

operator is used to create an object

syntax

set of rules that dictate how the words and symbols can be put together to form valid program statements; "grammar"

class libraries

sets of classes designed to be reusable components whose services can be used by many programs.

formal parameters

parameters in the method header

constant

placed at the class level (above the main method), written in all CAPS with underscores, and its initial value cannot be changed

println

prints a character string and then advances to the next line

object oriented programming

programming world-view in which things in the real world are modeled as software objects

service methods

public methods that offer useful behaviors to the client

boolean

represents a true or false condition

java.exe

represents the Java interpreter on your computer and is responsible for running your Java program

toString

returns a String that represents the object in some way

void

returns no value

accessor method

returns the current value of a variable; "getter"

coding standard

rules as to how source code should be formatted - makes code easier to read and debug

Java Class Library (JCL)

set of classes that are part of the JDK and documented in the Java API

method declaration

specifies the code that will be executed when the method is invoked

method header and method body

the two physical parts of a method are commonly called

public static void

the words required at the start of every "main" method definition

true

true or false: You find errors by testing and removing the discovered errors by debugging

white space

used to separate the elements (tokens) of the input; includes space characters, tabs, new line characters

constructor

used with the new operate to create an object and set its initial state. It looks similar to a method but has the same name as the class and has no return type

char

variable that stores a single character