Section 1 - Keywords

 

keyword is one of the words used to define the syntax of the Java programming language. The following are a few examples of Java keywords:

class public static void

 

Section 2 - Identifiers

 

An identifier is a valid name. Java defines the following rules for identifiers:

 

  • The first character must be an uppercase or lowercase letter, $, or _
  • Subsequent characters must be an uppercase or lowercase letter, $, _, or a digit
  • Identifiers may not contain punctuation or whitespace
  • Identifiers may not be the same as a keyword
  • There is no limit to the length of a Java identifier

 

The following are examples of valid Java identifiers:

hello1                
$mother        
_father                
BaBy                
 hello_world        

 

 

The following are examples of invalid Java identifiers:

1hello                (identifier may not begin with a digit)
hello world        (identifier may not contain whitespace)
hello;world        (identifier may not contain punctuation)

 

Java is a case sensitive language: baby, BABY, and BaBy are three different identifiers.

 

 

 

Copyright ©2017 by Ralph Lecessi Incorporated. All rights reserved.