Lecture on Displaying Messages in Java

Overview

Topics Covered:
- Strings in Java
- println and print methods
- System class

A string is a group of characters or text.
Strings must be enclosed in double quotes.
- Examples:
  - "hello"
  - "This is a string"
  - "1", "125" (as strings, not numbers)
An empty string: ""
Summary: Strings = characters between double quotes.

Purpose: Displays its parameter on the console.
Console Window: The output window where program results are shown.
Usage:
- Syntax: System.out.println(parameter)
- parameter typically a string.
- Ends with a semicolon (statement).
Example Code Execution:
- System.out.println("hello") prints "hello" (without quotes) and moves to a new line.
- System.out.println("123") prints "123" on a new line.
- Empty string System.out.println("") prints nothing but moves to a new line.
- System.out.println("456") prints "456" on a new line.
Key Points:
- ln in println stands for "new line."
- Moves cursor to a new line after printing.

Similar to println but doesn’t move to a new line.
Usage:
- Syntax: System.out.print(parameter)
Example Code Execution:
- Prints everything on the same line without line breaks.
- Example: "hello123456"
Key Points:
- No line break after printing.

out Object:
- An object of the PrintStream class.
- Contains print and println methods.
- Refers to the standard output device (screen).
System Class:
- Named with Pascal Case (capital S) indicating it's a class.
- out is a field of the System class (camel case, lowercase first letter).
Accessing Methods:
- Use dot operator . to access fields and methods.
- Syntax: System.out.print or System.out.println

Understanding how to print messages in Java using print and println methods.
System.out setup allows communication with the console output.

Note: Further exploration on displaying numbers instead of strings will be covered later.