Unit 1 · Lab 0

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

1

Open BlueJ

Launch BlueJ from your desktop.
6

Write Main Method

Add the main method skeleton.
2

Create Project

Project → New Project → Name it.
7

Compile

Click Compile; check for errors.
3

Open Existing Project

Project → Open Project… to open saved work.
8

Answer Questions

Read the sheet; write full sentences.
4

Create Class

New Class → Name it (capital letter first).
9

Test & Run

Right-click class → void main() → run.
5

Delete Default Code

Remove all boilerplate; start from scratch.
10

Handover Homework

Submit before the deadline.

🧱 The Skeleton

The mandatory structure for every program

Lab.java

Auto Align

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

Entrance

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

🧩 Lab Task Pattern

Each lab question is one task method, called from main.

Lab.java

🥇 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 the same as system. Java is very strict!

Brace Pairing

Every { must have a matching }

#1 Enemy

Watch out for Chinese punctuation: ；（）“” look similar but are not the same as Java's ; ( ) "".

🛠️ Keep Typing

Real progress comes from writing code, not just reading it.

Programming is a CRAFT. 🛠️

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

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