ICT 500 Descriptive Reviewer - Core Java Concepts & Programming Basics

50 vocabulary flashcards covering core Java concepts from the notes.

Programming

Writing instructions (code) that tell a computer how to perform tasks, automate decisions, and manipulate data; transforms input into output using logic, data structures, and control flow.

JVM

Java Virtual Machine; executes compiled Java bytecode and provides platform independence.

JRE

Java Runtime Environment; the JVM plus standard libraries required to run Java programs.

JDK

Java Development Kit; JRE plus development tools (javac, jar, debugger) needed to compile and build Java programs.

Write Once, Run Anywhere (WORA)

Java source is compiled to bytecode that runs on any OS with a JVM, enabling cross-platform deployment.

Platform independence

The ability of Java programs to run on different hardware/OS via the JVM, reducing platform-specific rewrites.

Public class

A class declared public whose name must match the filename (case-sensitive).

Class-name filename rule

A public class name must exactly match the .java filename (e.g., HelloWorld -> HelloWorld.java).

Primitive types

Basic value types (byte, short, int, long, float, double, char, boolean) that store raw values.

Reference types

Types that hold references to objects (e.g., String, arrays, custom classes); variables store addresses.

byte

An 8-bit integer primitive type.

short

A 16-bit integer primitive type.

int

A 32-bit integer primitive type.

long

A 64-bit integer primitive type.

float

A 32-bit floating-point primitive type.

double

A 64-bit floating-point primitive type.

char

A single 16-bit Unicode character.

boolean

A primitive type representing true/false states.

String

A sequence of characters; a reference type used for text.

BigDecimal

A class used for exact decimal numbers (currency) to avoid rounding errors with floating types.

Variable

A named storage location in memory whose value can change.

Identifier

The name used for a variable, method, or class; must follow naming rules.

Initialization

Assigning a value to a variable before use (required for local variables).

Default values

Predefined values for instance/static variables: numeric → 0, boolean → false, references → null.

final

A modifier that prevents reassignment; used to create constants.

Constant

A fixed value defined by a final variable.

Arithmetic operators

Operators +, -, *, /, % used for mathematical computations.

Relational operators

Operators ==, !=,

Logical operators

Operators &&, ||, ! used for boolean logic.

Assignment operators

Operators like =, +=, -= used to assign or update variable values.

String concatenation

Using the + operator to join strings and other values into one String.

Operator precedence

Rules determining the order of evaluation; e.g., */ before +-; can be overridden with parentheses.

Associativity

Direction of evaluation for operators with the same precedence (left-to-right in Java).

Expression

A combination of variables, literals, operators, and method calls that yields a value.

if statement

A conditional that executes its block when its Boolean expression is true.

if-else

Branching structure that selects between two blocks depending on a condition.

else if

Chains of mutually exclusive conditions; only the first true branch runs.

braces

Curly braces {} used to group statements and define scope; important for blocks.

Nested if

An if statement inside another if to form more complex decisions.

String equals

Use s1.equals(s2) to compare text content rather than == which compares references.

System.out.print

Outputs text without a newline.

System.out.println

Outputs text with a trailing newline.

Scanner

A class used to read input; commonly Scanner sc = new Scanner(System.in).

nextLine

Scanner method that reads an entire line of input.

close

Close a resource (e.g., Scanner) to release underlying streams.

Runtime error

An error occurring during program execution (e.g., NullPointerException).

Compilation error

An error that prevents code from compiling (syntax issues like missing semicolon).

Logical error

A bug where the program runs but yields incorrect results.

break

Exits the nearest loop immediately.

for loop

Loop with initialization, condition, update; best when the count is known.