Naming Conventions

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The choice of identifiers for various elements within a program can help improve the readability of the program. Identifiers should be descriptive of the element's purpose. The name of a class should be descriptive of the class's role or function. The name of a method should be descriptive of what the method does.

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The way names are spelled can also help improve a program's readability. Table A.1 summarizes the various conventions recommended by the Java Language Specification and followed by professional Java programmers.

Table A.1. Naming rules for Java identifiers

Identifier Type	Naming Rule	Example
Class	Nouns in mixed case with the first letter of each internal word capitalized.	OneRowNim TextField
Interfaces	Same as class names. Many interface names end with the suf.x "able."	Drawable ActionListener
Method	Verbs in mixed case with the first letter in lowercase and the first letter of internal words capitalized.	actionPerformed() sleep() insertAtFront()
Instance Variables	Same as method names. The name should be descriptive of how the variable is used.	maxWidth isVisible
Constants	Constants should be written in uppercase with internal words separated by _.	MAX_LENGTH XREF
Loop Variables	Temporary variables, such as loop variables, may have single character names: i, j, k.	int k; int i;