Getting Started with
BlueJ

Your first hands-on journey into the world of Java development.

Starting BlueJ

10 steps to get from zero to your first working program

01
Open BlueJLaunch BlueJ from your desktop.
06
Write Main MethodAdd the main method skeleton.
02
Create ProjectProject → New Project → Name it.
07
CompileClick Compile; check for errors.
03
Open Existing ProjectProject → Open Project… to open saved work.
08
Answer QuestionsRead the sheet; write full sentences.
04
Create ClassNew Class → Name it (capital letter first).
09
Test & RunRight-click class → void main() → run.
05
Delete Default CodeRemove all boilerplate; start from scratch.
10
Handover HomeworkSubmit before the deadline.

The Skeleton

The mandatory structure for every program

Lab.java
java

Auto Align

Use Cmd + Shift + I to fix your indentation instantly.

Entrance

Remember: main method is the "Entrance Doorway" 🚪.

Golden Rules

Beginner's guide to avoid critical pitfalls

Input Method

Always use English mode for symbols like ; ( ) { }

Semicolons

Every statement must end with a semicolon ;

Case Sensitivity

System is NOT same as system. Java is very strict!

Brace Pairing

Every { must have a matching }
The Chinese punctuation ； is your #1 enemy!

Lab Summary

Congratulations on your first steps!

Programming is a CRAFT. 🛠️

Reading docs 10 times
isn't as good as typing code ONCE.

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