Java Naming Conventions

Below are some naming conventions of for java programming language. They must be followed while developing software in java for good maintenance and readability of code. Java uses CamelCase as a practice for writing names of methods, variables, classes, packages, and constants.

Naming Conventions Table:

Camel case in Java Programming: It consists of compound words or phrases such that each word or abbreviation begins with a capital letter or first word with a lowercase letter, rest all with capital.

èClasses and Interfaces :

§  Class names should be nouns, in mixed case with the first letter of each internal word capitalized. Interfaces name should also be capitalized just like class names.

§  Use whole words and must avoid acronyms and abbreviations.

Examples:

Interface  Bicycle

Class MountainBike implements Bicyle

Interface Sport

Class Football implements Sport

    èMethods :

§  Methods should be verbs, in mixed case with the first letter lowercase and with the first letter of each internal word capitalized.

Examples:

void changeGear(int newValue);

void speedUp(int increment);

void applyBrakes(int decrement);

    è Variables: Variable names should be short yet meaningful.

§  Should not start with an underscore(‘_’) or dollar sign ‘$’ characters.

§  Should be mnemonic i.e, designed to indicate to the casual observer the intent of its use.

§  One-character variable names should be avoided except for temporary variables.

§  Common names for temporary variables are I, j, k, m, and n for integers; c, d, and e for characters.

Examples:

    // variables for MountainBike class

    int speed = 0;

    int gear = 1;

    èConstant variables:

§  Should be all uppercase with words separated by underscores (“_”).

§  There are various constants used in predefined classes like Float, Long, String etc.

Examples:

static final int MIN_WIDTH = 4;

// Some  Constant variables used in predefined Float class

public static final float POSITIVE_INFINITY = 1.0f / 0.0f;

public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;

public static final float NaN = 0.0f / 0.0f;

   è Packages:

§  The prefix of a unique package name is always written in all-lowercase ASCII letters and should be one of the top-level domain names, like com, edu, gov, mil, net, Org.

§  Subsequent components of the package name vary according to an organization’s own internal naming conventions.

Examples:

com.sun.eng

com.apple.quicktime.v2

// java.lang packet in JDK

java.lang