Java for Absolute Beginners – Vocabulary Flashcards

A concise set of vocabulary flashcards covering fundamental Java concepts and terminology introduced in the lecture/book "Java for Fucking Idiots."

Java

A high-level, object-oriented programming language that compiles to bytecode and runs on the Java Virtual Machine.

Programming Language

A human-readable set of rules and syntax used to write instructions that computers can execute after compilation or interpretation.

Source Code

The human-written text of a program before it is compiled.

Compiler

A tool that translates source code into another form (e.g., bytecode or machine code) so a computer can run it.

Bytecode

The platform-independent instructions produced by the Java compiler; executed by the JVM.

Java Virtual Machine (JVM)

Software that runs bytecode and translates it into machine instructions for the host CPU, enabling “write once, run anywhere.”

Java Development Kit (JDK)

Oracle’s bundle that includes the compiler, JVM, standard library, and other developer tools.

Class

A blueprint that defines the properties and methods of objects created from it.

Object (Instance)

A specific realization of a class, with its own data and the ability to execute the class’s methods.

Property (Field)

A variable declared inside a class that stores data describing each object’s state.

Method

A block of code in a class that performs actions or computes and returns values; the verbs of an object.

Constructor

A special method that runs when an object is created and initializes its state.

Static

A keyword marking members that belong to the class itself rather than to any object instance.

Variable

A named storage location that holds a value which can change during program execution.

Primitive Data Type

Built-in, non-object value types such as byte, short, int, long, float, double, char, and boolean.

String

An object representing a sequence of characters; immutable and rich with helper methods.

Array

A fixed-size, ordered collection of elements of the same type, accessed by index.

Index

The zero-based position number used to access an element inside an array.

Loop

A control structure that repeatedly executes a block of code while a condition remains true.

While Loop

A loop that tests its condition before each iteration and continues while the condition is true.

For Loop

A loop that combines initialization, condition check, and iteration step in one line; ideal for stepping through arrays.

Enhanced For Loop

A simplified ‘for-each’ loop that iterates over every element in a collection without manual indexing.

If Statement (Conditional)

A control structure that executes code only when a specified boolean expression evaluates to true.

Operator

A symbol (e.g., +, -, *, /, &&, ||, ==) that performs arithmetic, logical, or relational operations on values.

Assignment Operator (=)

Sets the variable on the left to the value produced on the right.

Comparison Operator (==, !=,

Checks relationships between two values and returns a boolean result.

Logical Operators (&&, ||, !)

Combine or negate boolean expressions: AND, OR, and NOT.

Modulo Operator (%)

Returns the remainder of integer division; useful for tasks like checking even/odd numbers.

Concatenation

Joining strings (or strings with other values) using the + operator to form a single string.

String Immutability

Property whereby operations on a String produce new String objects instead of altering the original.

main Method

The entry point of every Java application: public static void main(String[] args).

Parameter

A variable in a method or constructor declaration that receives a value when the method is called.

Argument

The actual value passed to a method or constructor to satisfy a parameter.

Return Type

The data type of the value a method provides back to its caller; void indicates no return value.

Null

A special literal representing the absence of any object reference.

NullPointerException

A runtime error thrown when code tries to use a null reference as if it pointed to an object.

Overloading

Defining multiple constructors or methods in the same class with the same name but different parameter lists.

Access Modifiers

Keywords controlling visibility: public, protected, (package-private), and private.

Package

A namespace and matching folder structure used to group related classes and avoid naming collisions.

Import Statement

A line that brings a class or package into scope so it can be referenced without its full package name.

Break Statement

Exits the nearest loop or switch immediately.

Continue Statement

Skips the rest of the current loop iteration and proceeds to the next one.

Abstraction

Design principle of exposing only necessary details while hiding internal complexity.

Encapsulation

Restricting direct access to an object’s internal data by using access modifiers and public methods.

Inheritance

Creating a new class that acquires the properties and methods of an existing class (extends).

Polymorphism

The ability to treat objects of different subclasses through a common parent type, with the correct overridden methods executing at runtime.

Constructor Overloading

Providing multiple constructors with different parameter lists to create objects in varied ways.