ZyBooks COS 160 USM Final

escape sequence

- a series of characters that represents a special character - begins with a backslash character (/)

Bytecode interpreter

- a software tool that translates bytecode into machine language and executes it - a.k.a. "Just-in-time compiler"

compile-time errors

- syntax errors and other basic problems - if these exist, an executable version of the program is not created (there will be no .class file)

unary minus

- used as negative

string concatenation operator (+)

- used to append one string to the end of another -it can also be used to append a number to a string

What are the three types of errors that a program can have?

1) Compile-time errors 2) Run-time errors 3) Logical errors

What does the Java compiler do?

The Java compiler translates Java source code into a special representation called bytecode.

block

a brace-enclosed {...} sequence of statements , such as found with an if-else, for loop, or while loop

InputStream

a class that supports input provides several overloaded

OutputStream

a class that supports output provides several overloaded methods for writing a sequence of bytes to a destination. That sequence is normally placed into a buffer, and the system then outputs a buffer at various times

interface

a class' public member methods

expression

a combination of items, like variables, literals, and operators, that evaluates to a value

loop

a construct that repeatedly executes specific code as long as some condition is true

default constructor

a constructor that can be called without any arguments

type conversion

a conversion of one data type to another (such as an int to a double)

abstract data type (ADT)

a data type whose creation and update are constrained to specific well-defined operations

exception

a detected runtime error that commonly prints an error message and terminates the program

block (a.k.a. block statement)

a list of statements surrounded by braces

method

a list of statements that can be executed by referring to the method's name

nested loop

a loop that appears in the body of another loop

infinite loop

a loop that will always execute (i.e., execute infinitely) because the loop's expression always evaluates to true

member method

a method that is a part of (a "member of") a class

identifier

a name created by a programmer for an item like a variable or method (must be a sequence of letters (a-z, A-Z, _ , $) and digits (0-9) and must start with a letter)

method

a named list of statements

floating-point literal

a number with a fractional part (even if the fraction is 0, as in 1.0 or 0.0)

System.out

a predefined output stream object reference that is associated with a system's standard output automatically reads the standard input from a memory region, known as a buffer, that the operating system fills with the input data

while loop

a program construct that executes a list of sub-statements repeatedly as long as the loop's expression evaluates to true

boolean

a quantity that has only two possible values, true or false

scope

a region of code were a declared name is valid

testbench (a.k.a. test harness)

a separate program whose sole purpose is to check that a method returns correct output values or a variety of input values

string

a sequence of characters

compiler

a software tool which translates source code into a specific target language

constructor

a special class member method that is called automatically when a variable of that class is allocated, and which can be used to initialize all fields has the same name as the class has no return type (not even void)

literal

a specific value in code (like 2)

break statement

a statement in a loop that causes an immediate exit of the loop

continue statement

a statement in a loop that causes an immediate jump to the loop condition check

operator

a symbol for a built-in language operation

javadoc

a tool that parses specially formatted multi-line comments to generate program documentation in HTML format

escape sequence

a two-character sequence starting with \ that represents a special character (Ex. '\n' represents a newline character)

field (a.k.a. class member)

a variable declared within a class but outside any method

reference variable (a.k.a. reference type)

a variable of class type

call by value

a variable of primitive type (like int or char) is passed to a method by passing the value of the variable the argument value is copied into a local variable for the parameter

char

a variable of this type can store a single character (like the letter m or the symbol %)

double

a variable of this type stores a floating-point number

reserved word (keyword)

a word that is part of the language, like int, short, or double

logical errors

happens when a program runs, but produces incorrect results, perhaps from using an incorrect comparison or formula

method call

invokes a method's name and causes the method's statements to execute

method call

invoking a method

public

members of a class that are declared with this visibility can be referenced anywhere

private

members of a class that are declared with this visibility can be referenced only within that class

method stubs

method definitions whose statements haven't been written yet

overflow

occurs when the value being assigned to a variable is greater than the maximum value the variable can store

run-time errors

problems that occur during execution, such as trying to divide by zero, which causes a program to terminate abnormally

compound operators

provide a shorthand way to update a variable (E.g. +=, -=, /=, %=)

parameter

provides input to a method influences method behavior like a variable declaration; indicates the type followed by the parameter name

IOException

provides mechanisms for exception throwing and handling

braces {} (a.k.a. curly braces)

represent a grouping, such as a grouping of statements

collection

represents a generic group of objects known as elements

variable

represents a memory location used to store data

regression testing

runs an existing testbench whenever code is changed checks to see whether the change caused code to "regress", meaning to fail previously-passed test cases

short circuit evaluation

skips evaluating later operands if the result of the logical operator can already be determined

assignment statement

stores (i.e. assigns) the right-side item's current value into the variable on the left side

throws clause

tells the Java Virtual Machine that the corresponding method may exit unexpectedly due to an exception

border cases

testing fringe scenarios to see if the program fails

member access operator

the "." operator, which a member-method call uses

scope

the part of the program where the name of a defined variable or method item is visible starts after the declaration until the method's end

debugging (a.k.a. troubleshooting)

the process of determining and fixing the cause of a problem in a computer program

unit testing

the process of individually testing a small part or unit of a program, typically a method

loop body

the sub-statements inside the braces of a while loop

argument

the value passed to a parameter an expression (such as 99, numCars, or numCars + 99)

PrintStream

this class extends the base functionality of the OutputStream class and provides the print() and println() methods for converting different types of data into a sequence of characters

class

this construct defines a new type that can group data and methods to form an object

accessor (a.k.a. getter)

this method accesses fields but may not modify them

return

this method causes execution to jump back to the original calling location

mutator (a.k.a. setter)

this method may modify ("mutate") the class' fields

new

this operator is used to explicitly allocate an object

void

this return type indicates that a method does not return any value

switch statement

this statement can more clearly represent multi-branch behavior involving a variable being compared to constant values The program executes the first case whose constant expression matches the value of the switch expression, executes that case's statements, and then jumps to the end. If no case matches, then the default case statements are executed.

logical operator

treats operands as being true or false, and evaluates to true or false

method name overloading

when a program has multiple methods with the name name but differing in the number or types of parameters

type casting

when a programmer precedes an expression with "(type) expression" to convert the expression's value to the indicated type

code coverage

when all code is executed at least once

row-major order

when each row follows the previous row

array

an ordered list of items of a given data type

Arraylist

an ordered list of reference type items

reference type variable

can refer to an instance of a class, also known as an object

for loop statement

collects three parts - the loop variable initialization, loop expression, and loop variable update- all at the top of the loop

assert statement

commonly used to check for correct execution

conditional expression form

condition ? expreWhenTrue : expreWhenFalse

object

consists of some internal data items plus operations that can be performed on that data

method definition

consists of the new method's name and block of statements

stack frame

corresponds to a call to a subroutine which has not yet terminated with a return contains: 1) method parameters 2) return address 3) local variables

loop variable

counts the number of iterations of a loop

enumerator type

declares a name for a new type and possible values for that type

primitive type variable

directly stores the data for that variable type, such as int, double, or char

branching

directs a program to execute either one statement group or another, depending on an expression's value

iteration

each execution of the loop body of a while loop

element

each item in an array

test vector

each unique set of input values in a testbench

primitive wrapper classes

allow the program to create objects that store a single primitive type value, such as an integer or floating-point value provide methods for converting between primitive types, between number systems, and between a primitive type and a String representation

FileInputStream

allows a programmer to read bytes from a file

call by reference

an array is passed to a method by passing a reference to the array the array reference is copied to the method's parameter, so a method can modify the elements of an array argument

exception

an event that disrupts a program's execution

constant variable (final variable)

an initialized variable whose value cannot change

argument

an input value to a method that appears between parentheses