Java Fundamentals, Variables, Methods, and Classes Vocabulary

Vocabulary flashcards covering core Java concepts including basic syntax, variables, data types, methods, strings, constructors, accessors, mutators, arithmetic shortcuts, and object-oriented principles.

Main Method

The execution entry point of any Java program, specified by the header public static void main(String[] args).

String

A complex data type in Java representing a sequence or collection of characters enclosed in double quotation marks.

System.out.print()

A Java method that displays the provided string in the output console and keeps the cursor on the same line after printing.

System.out.println()

A Java method that displays the provided string in the output console and moves the cursor to the next line after printing.

Escape Sequences

Special character combinations starting with a backslash used to represent characters that are difficult to include in strings, such as \n (new line), \t (tab), \" (double quote), \' (single quote), and \ (backslash).

Variable

A designated location set aside in memory reserved to store a specific type of data.

Variable Declaration

A statement that instructs the computer to create a variable of a specified data type and assign it a reference name.

Variable Initialization

The act of assigning an initial data value to a variable before it can be used in a program.

Primitive Data Types

Built-in basic Java data types that store values directly, consisting of int, double, char, and boolean.

Reference Variables

Variables declared to store complex data types or objects, which store a memory address reference to the object rather than the object itself.

Java Naming Convention

The identifier naming rule where variable names start with a lowercase letter, contain no spaces, and capitalize the first letter of each subsequent word.

Assignment Statement

A statement in Java that assigns a value to a variable using an equals sign.

Calling a Method

The syntax command used to execute a method on an object or class, written by placing a period after the object or class name followed by the method name and parentheses.

String Concatenation

The process of joining two or more strings or values together using the plus + operator.

Method Arguments (Parameters)

The values or variables passed inside a method's parentheses that the method requires in order to execute.

Return Value

The data value computed and returned by a method upon completion, which can be of any primitive or complex data type.

void

A Java keyword used as a method's return type when the method performs a function but does not return a value.

String Indexing

A zero-based positional mapping system for characters in a string, where index $0$ represents the first character and the final index is always $\text{length} - 1$.

Object State

The current cumulative status or condition of an object resulting from all executed methods, which is stored in its state or instance variables.

Instance Variables (Fields)

Variables defined within a class that store values determining the specific state of an object.

Constructor

A special class member that creates an instance of a class and initializes all of its fields, matching the exact name of the class and having no return type.

Accessor Method

A method designed to allow a programmer to find or retrieve the current value of an object's state variable, such as getBalance().

Mutator Method

A method designed to allow a programmer to modify or change the current value of an object's state variable, such as setBalance().

Test Class

A class written to test and verify how methods of another class operate in practice.

Class Instantiation

The command syntax that instructs the computer to create an object from a class using the new keyword followed by a constructor call.

Compound Assignment Operators

Java shortcut operators including +=, -=, *=, and /= that update and reassign a variable relative to its current value.

Increment Operator

The Java shortcut operator ++ that adds $1$ to an integer variable (for example, i++ is equivalent to i = i + 1).

Method Header

The signature line declaring a method, which includes its access modifier, return type, method name, and parameters.