Basic Syntax

Programs made up of statements

  • statements end with a semicolon
  • parts separated by zero or more witespaces

System.out.println("Welcome to Java");

Reasons for writing comments

  • for wirting human readable notes

  • to hide the code from compiler

Types of comments

// line comments

/* Block comment
Text ignored within the block

 Javadoc comment
 compiler treats similar to block comment,

 can be used to generate documentation

Packages in Java

Packages provide organization Follow standard naming convention Affect source code structure

Package name conventions

  • All lowercase.
  • use reverse domain name notation to assure global uniqueness.
  • add further qualifiers to assure uniqueness within a company or group

package com.pluralsight; package; package com.pluralsight.sales; package com.pluralsight.sales.accountmanagement;

Type names are qualified by their package


package com.pluralsight.example;
public class Main {
    public static void main(String[] args){

Package Names Affect Source Code Organization

Pakcage names affect the souce code organization src->com->pluralsight->example->


Named data storage
Strongly typed


int dataValue;
dataValue = 100;

int myInfo = 200;

Variable Naming

Use only letters and numbers
first charcter cannot be a number

int total;
int grade4;

Style names using camel case
start each word after the first with uppercase
all other letters are lower case

int sum;
int studentCount;
int bankAccountBalance;
int level12Training;

// unintalized, only declared variable example;

int myVar;

// intialized variable
myVar = 50;

variables can be declared final
values cannot be changed once set
helps avoid errors caused by indadvertent variable changes


final int maxStudents = 25;
// final variable can be declared without intialization, but once the value is set compiler will not be allow us to change it again.
final int someVariable;

int someOtherVariable = 100;

someVariable = someOtherVariable;

Primitive Data Types

  • Built into the language
  • Foundation of all the other types
  • Four Categories
    • Integer
    • Floating point
    • Character
    • Boolean


TypebitsMin Valuemax ValueLiteral form

Floating Point Types

store values containing a fraction portion. Literal values placed between single qoutes. for unicode code points, use \u followed by 4-digit hex value

TypebitsMin Valuemax ValueLiteral form
float321.4 * 10 rais to power -453.4 * 10 raise to power 380.0f
double644.9 * 10 rais to power -3241.7 * 10 raise to power 3080.0 or 0.0d

Character Data Types

Stores a single unicode charcter Literal values placed between single quotes

char regular = 'U';
char accentedU = '\u00DA';

Boolean Type

Stores ture/false values Literal values are true and false

Primitive data types are stored by values

It means that each variable gets its own independent copy of each value.

int firstValue = 100;

// otherValue varriable will have it's own value which is hundred in this case and otherValue and firstValue has no link or relationship after assignment.

int otherValue = firstValue;

Arithmetic Operators


Produce a result, No impact on values used in the operation.


Increase or decrease a value Replace orignal value.

++ Increment value by 1

Dccrement value by 1

Order Matter Prefix applies operation before returning value ``+

Postfix applies operation after returning value

Compound Assignment

operate on a value replace orignal value