Starting with variables

Introduction to Java

Jim White

Java Developer

Variables are boxes

A box labeled as Books, equivalent to a variable

Boxes store different information

A second box labeled Kitchen

Variables have type, name, and value

Every variable has a type, name, and value

Assigning variables - String keyword

String

Components:

String keyword

Assigning variables - name

String variableName

Components:

String keyword
Variable name

Assigning variables - syntax

String variableName =

Components:

String keyword
Variable name
= to assign value

Assigning variables - text

String variableName = "text in double quotation marks";

Components:

String keyword
Variable name
= to assign value
The actual value
Semicolon ;

// Example
String message = "Hello, Java!";

Assigning variables - whole numbers

Use int for whole numbers

int age = 29;

Equal sign doesn't mean equal

Single equal sign is an assignment operator

Variables have a type

We need to specify a type when declaring a variable, such as String for a text variable

Naming convention

Good variable names use CamelCase

Using variables

class InfoAboutJava {
  public static void main(String[] args) {

    String message = "Java is awesome!";

    // Print the message variable
    System.out.println(message);
    }
}

Java is awesome!

Summary

Variables store values
type variableName = value;
Variable names:
- Start with letter
- Follow camelCase
- Cannot contain space

Use variables instead of their value

class InfoAboutJava {
public static void main(String[] args) {  

  String message = "Java is awesome!";

  // Using variable directly
  System.out.println(message);
  }
}

Let's practice!

Introduction to Java