Java Naming Standards...

Rules

• Identifiers (variables, classes, methods, packages and interface) must be composed of letters, numbers, underscore ( _ ) or dollar sign ( $ ).
• Identifiers must begin with letter, underscore or dollar sign.
• Keywords cannot be used as identifiers.
• Spaces are not allowed between the words.
• Variables can have any length.

  Ex: apple, _apple, $apple, Apple123, _123apple

• There are examples for illegal identifiers.

  Ex: 123mango, Mango#, Fresh mango, _1@mango

Java key words

abstract	boolean	break	byte	case	catch
char	class	const	continue	default	do
double	else	extends	final	finally	float
for	goto	if	implements	import	instanceof
int	interface	long	native	new	package
private	protected	public	return	short	static
strictfp	super	switch	synchronized	this	throw
throws	transient	try	void	volatile	while
assert	enum

Classes and interfaces naming standards

• The first letter should be capitalized and camel case is allowed. 
• Class names should be nouns.
• Ex: Apple, MyMobile 

• Interfaces names should be adjectives.
• Ex: Readable 

Methods, variables and constants naming standards 

• Method names and variable names should be started with lowercase and other words should be in Upper case (camel case). 
• Method names typically be verb-noun pairs.
• Examples for methods: doCalculation( ), getName( )
• Examples for variables: name, userName 

• All the letters should be in uppercase in constants. Other words should be separated by underscore. 

                Ex: MAX_LENGTH , TOP_LEVEL 

JavaBeans Standards 

JavaBeans property naming rules

• If the property is not a Boolean, then getter method's prefix must be ‘get’.

                Ex: getSize( ), getName( ) 

• If the property is Boolean, the getter method’s prefix is either ‘get’ or ‘is’.

                Ex: getStopped( ), isStopped( ) 

• The setter method’s prefix must be ‘set’.

                Ex: setSize( ) 

• Setter method signatures must be marked public with a void return type and an argument that represents the property type. 
• Getter method signatures must be marked public that take no arguments and have a return type that matches the argument type of the setter method for that property. 

JavaBean Listener naming rules

• Listener method names used to “register” a listener with an event source must be the prefix ‘add’ followed by the listener type.
• Ex: addActionListener ( ) 

• Listener method names used to remove (“register”) a listener must use the prefix remove, followed by the listener type. 

• Listener method names must be end with the word “Listener”. 

Comments in java 

//this is single line comment 

/* Multi line comment 

 * Multi line comment 

 * Multi line comment 

 */

/** 

 *Documentation comment 

 * 

 */