This document serves as a lecture outline on programming with Java, covering its definition, history, data types, variable declaration, naming conventions, value assignments, and printing assigned values. Java is described as a versatile, platform-independent language created in the mid-1990s, with various primitive and non-primitive data types. Additionally, it emphasizes that Java allows for 'write once, run anywhere' functionality, making it applicable across different computing environments.

1. Programming
with JAVA
Lecturer: Isuri Rajapaksha

2. Content
• What is java
• History of Java
• Data Types
• Variables
• Value assigning
• Printing assigned values

3. What is Java?
• Java is a special language computers understand.
• Easy Language: Java is like a common language that helps us talk to
computers and make them do what we want.
• Works Everywhere: (Platform Independence) -Imagine writing a message
that anyone can read, no matter what language they speak. Java is a bit like
that—it works on many different types of computers without needing
changes.
• "Write Once, Run Anywhere": With Java, we write our instructions just once,
and they can work on any computer that knows Java.
• Java is used to make lots of things, like games, apps for phones, websites, and
even big computer systems used by companies.

4. History of Java
• Creation: Java was created by James Gosling and his team at Sun
Microsystems in the mid-1990s.
• Purpose: It was designed to be a versatile, platform-independent
language for small devices and embedded systems initially.
• Evolution and Impact
• Versions: Over time, Java evolved with new versions, adding features
and improvements for developers.
• Oracle's Involvement: Oracle Corporation acquired Sun Microsystems
in 2010, taking over Java's development and support.

5. Data Types
• 1. Primitive Data Types:
• Primitive data types are the basic data types that are built into the
Java language. They represent single values and are not objects. There
are eight primitive data types in Java.
• 2. Non-Primitive (Reference) Data Types:
• Non-primitive data types are not predefined in Java. They are created
by the programmer and are derived from primitive types. They are
also known as reference types because they reference objects.

6. 1. Primitive Data Types:

7. 2.Non-primitive data types
• Non-primitive data types are not predefined in Java. They are created
by the programmer and are derived from primitive types. They are
also known as reference types because they reference objects. Some
common non-primitive data types include:
• Arrays: Collections of elements of the same type stored in contiguous
memory locations.
• Strings: Sequences of characters, treated as objects in Java, although
not primitive types.
• Objects: Instances of classes, comprising attributes (variables) and
behaviors (methods).

8. Variables
• Declaration of Variables:
• Memory Reservation: When we declare a variable in Java, we're
informing the computer's memory to allocate space for that variable
based on its data type.
• ex: int x = 10;

9. Variable Naming Conventions in Java:
• Start with a Letter or Underscore:
• Variable names must begin with a letter (A-Z or a-z) or an underscore (_).
• They cannot start with a number or special characters (except underscore).
• Use Alphanumeric Characters and Underscore:
• After the initial letter, variable names can include letters, numbers, or
underscores.
• Special characters (like *, $, %, etc.) are not allowed in variable names.
• No Spaces or Reserved Words:
• Variable names cannot contain spaces or tabs.
• Avoid using keywords(int.float)
• Case sensitive

10. Value Assigning
• Assigning a value to a variable means storing a specific piece of
information in that variable.
• Ex :
• int x = 5;
• int number = 10;
• double decimal = 3.14
• char letter = 'A';

11. Printing Assigned Values:
• System.out.println(): It's a function provided by Java to show
information or results of a program to the user.
• System.out.println(“hello ,World ! “);

12. Thank You!