Unit 2 - Class Structure and Design

assignment

using the assignment operator ( = ) to initialize or change the value stored in a variable

data type

the format of the data that can be stored in a variable

declaration

giving a name and data type to a variable

initialization

giving a starting value to a variable using the assignment operator ( = )

literal

a source code representation of a value, such as a number or text

primitive type

a basic data type that Java predefines

reference type

a data type that contains a pointer to the memory location of an object

variable

a container that stores a value in memory

ArithmeticException

an error caused by dividing by zero

compound assignment operator

shortcut syntax ( += , -= , *= , /= , %= ) to perform an operation (+ , - , * , / , or % ) on both operands and store the result into the variable on the left

compound expression

a combination of expressions

expression

a combination of data and operators that evaluates to a single value

operand

the data that is operated on

truncate

to cut off data from the end

access modifier

a keyword used to set the visibility of classes, variables, constructors, and methods

encapsulation

an object-oriented programming concept where the instance variables of a class are hidden from other classes and can be accessed only through the methods of the class

instance variable

a variable defined in a class that represents an attribute of an object

actual parameter

the value given to an attribute when initializing an object

call by value

copying the value of the actual parameter to the constructor's formal parameter

default value

a predefined value that is used by a program when the user does not provide a value

formal parameter

the values to be passed to a constructor or method

local variable

a variable declared and accessible within a specific block of code

no

argument constructor - a constructor with no parameters

overloading

defining two or more constructors or methods with the same name but different signatures

parameterized constructor

a constructor that has a specific number of arguments to be passed to assign values to an object's instance variables

NullPointerException

an error that occurs when a reference does not point to an object

null

indicates that the variable does not refer to any object

application program interface (API)

a library of prewritten classes

library

a collection of methods or reusable components of code

DRY principle

a software development principle that stands for "Don't Repeat Yourself" which aims to reduce repetition in code

refactor

to improve the readability, reusability, or structure of program code without altering its functionality

return keyword

exits a method and provides the value to where the method is called

accessor method

gives the value stored in an instance variable

return by value

a copy of the value is given to where the method is called

return type

the type of the value to be given from the method

Boolean expression

a logical statement that gives either a true or false value

Sentinel Value

a special value used to notify the program to stop accepting input

mutator method

changes the value stored in an instance variable

relational operator

an operator used to compare values or expressions

escape sequence

starts with a \ to indicate how to display a String

override

to define a method in a subclass with the same method signature as a method inherited from a superclass

this keyword

a keyword used to refer to the current object in a method or constructor

scope

where a variable can be used