1. Introduction to Java Programming
Lecture 2
Introduction to Java Programming

5. Java Class Format
public class userDefinedName { public static void main(String[] args){ } }

7. 2.2 Primitive Data Types

16. Lexical Elements
Keywords
Literals
Identifiers
Operators
Punctuation

17. Can not be used for any other purpose All lowercase letters
Keywords
abstract default if private this boolean do implements protected throw break double import public throws byte else instanceof return transient case extends int short try catch final interface static void char finally long strictfp volatile class float native super while const for new switch continue goto package synchronized
Can not be used for any other purpose
All lowercase letters

18. Literal
A literal is the source code representation of a value of a primitive type or the String type
Data type Literal Examples int double d char ‘b’ boolean true String “Hello World”

19. variable names class names constants Identifiers
An identifier is an unlimited-length sequence of Java letters and Java digits, the first of which must be a Java letter. An identifier cannot have the same spelling as a keyword or boolean literal.
Example identifiers sum prod root1 isLeapYear Quadratic LeapYear MAX
variable names
class names
constants

20. Operators

21. Punctuation
The following nine ASCII characters are the separators (punctuators): ( ) { } [ ] ; ,

22. White Space
White space is defined as the ASCII space, horizontal tab, and form feed characters, as well as line terminators

23. There are two kinds of comments:
/* text */ A traditional comment: all the text from the ASCII characters /* to the ASCII characters */ is ignored by the compiler
// text A end-of-line comment: all the text from the ASCII characters // to the end of the line is ignored by the compiler.

24. All variables must be defined
Tell the compiler the
name of each variable
type of each variable
int x; int y; boolean isLeapYear; boolean isPerflick; double root1; double root2;
int x, y; boolean isLeapYear, isPerflick; double root1, root2;

25. Initializing variables
int x = 5; int y; //y need not be initialized
y = 2*x + 1; …