Introduction to Programming
Introduction to core programming ideas, Java's role, and the compile–run cycle.
Introduction to Programming is a free Java Academy lesson on CoddyKit — lesson 1 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Java Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What Is Programming
What is programming? Programming is the act of writing exact instructions that a computer can follow. Computers are fast and literal: they do exactly what we tell them, no more and no less.
- We use programming languages to express instructions.
- Instructions must be unambiguous and ordered.
- Small steps make complex tasks manageable.
Why Java
Why Java? Java is a general-purpose, object-oriented language used for servers, Android, tools, and more.
- Portable: write once, run on many platforms (via the JVM).
- Mature ecosystem: libraries, frameworks, and strong community.
- Performance: just-in-time compilation and modern JVMs.
Compile and Run
How does Java run?
- You write human-readable
.javasource code. javaccompiles it to.classbytecode.- The JVM executes bytecode on your machine.
This two-step approach (compile then run) makes Java portable and fast.
JDK JRE JVM
JDK vs JRE vs JVM
- JDK (Java Development Kit): tools for developers (includes the compiler
javac). - JRE (Java Runtime Environment): libraries to run Java apps.
- JVM: the engine that executes Java bytecode.
Pipeline: .java → javac → .class → JVM executes.
Algorithm and IPO
Algorithm & IPO
- Algorithm: a finite, clear set of steps to solve a problem.
- Input → Process → Output (IPO) helps you model problems.
- Design tiny steps; test them frequently.
Example: read a number (input), double it (process), print the result (output).
Key Vocabulary
Key vocabulary
- Variable: a named place to store a value.
- Expression: values and operators that produce a result.
- Statement: a complete instruction (ends with a semicolon in Java).
- Method: a reusable block of code with a name.
- Class: the blueprint for objects; Java code lives inside classes.
Concept Check
Quick check: Which option best defines a computer program?
Recap and Next
Recap: You learned what programming is, why Java is popular, and how Java uses the compiler and JVM. You also met the JDK/JRE/JVM trio and key vocabulary.
Next: Install the JDK and pick an IDE so you can write and run code.
Frequently asked questions
Is the “Introduction to Programming” lesson free?
Yes — the full text of “Introduction to Programming” is free to read here on the web, and the Java Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Java Academy course, upgrade to CoddyKit PRO.
What will I learn in “Introduction to Programming”?
Introduction to core programming ideas, Java's role, and the compile–run cycle. You practise Java Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Java Academy?
No prior experience is required. Java Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 3, so you can start here or from the beginning and move at your own pace.
How long does the “Introduction to Programming” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Java Academy lesson?
Yes. Every Java Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Introduction to Programming
- Installing JDK & IDE
- Writing First Program