Starting Java can feel different if you’re coming from Python or another language where you “install one thing and go.” With Java, you’re usually setting up two pieces:
The Java Development Kit (JDK) – this is what lets you compile and run Java programs.
An editor/IDE (like NetBeans, IntelliJ, or Eclipse) – this is where you write code and run projects.
The good news: once Java is installed correctly, the learning becomes much smoother. This post is written for beginners, by a beginner, to explain what to install, what to expect, and how Java’s object-oriented programming (OOP) mindset changes how you design programs.
Java Installation (High-Level Guidance)
Instead of a step-by-step walkthrough, here’s the “big picture” so you know what you’re doing and why:
1) Pick a JDK (this matters).
Most beginners choose one of these:
Eclipse Temurin (OpenJDK): a popular free option that works well across platforms.
Oracle JDK: the “official” Oracle distribution (commonly referenced in courses and tutorials).
2) Choose an IDE that reduces friction.
An IDE helps you avoid command-line issues early on and makes it easier to compile/run programs:
NetBeans, IntelliJ IDEA Community Edition, or Eclipse are common beginner choices (your course may recommend specific ones).
3) Confirm Java is actually working.
A simple check is running a basic program (like Hello World) and confirming your IDE is pointing to the correctly installed JDK. If something breaks, it’s usually one of these:
Your IDE is pointing to a different JDK than the one you installed
Your system has multiple Java versions installed
Your PATH/JAVA_HOME settings are misconfigured (mostly affects command line)
If you want the most beginner-friendly explanations of Java concepts and setup, Oracle’s Java Tutorials are a reliable “source of truth.”
What “Object-Oriented Programming” Actually Means
OOP is a way of designing software around objects (things) instead of just procedures (steps).
In Java, you’ll constantly think in terms of:
Classes: blueprints
Objects: the real “instances” created from those blueprints
Methods: behaviors (what an object can do)
Fields: state/data (what an object has)
Oracle defines an object as a bundle of state and behavior—that single sentence helped me understand why Java feels more structured than some other languages.
The 4 Major Principles (The “Four Pillars” of OOP)
Most beginner OOP lessons revolve around these four ideas:
1) Encapsulation (Protect and organize data)
Encapsulation means bundling data + methods together inside a class, and controlling access to that data.
In practice, this is why you’ll see private fields and public methods (getters/setters). Encapsulation is a big reason OOP systems are easier to maintain: it reduces the chance that random parts of your program can change critical data unexpectedly.
Beginner example:
A BankAccount object shouldn’t let any code directly change the balance. Instead, you call a method like deposit() or withdraw() so rules are enforced.
2) Abstraction (Hide complexity, show what matters)
Abstraction is about exposing a simple interface while hiding complicated details. You can use something without knowing every internal step.
Beginner example:
When you drive a car, you use the steering wheel and pedals; you don’t manage combustion timing. In Java, abstraction is why classes can offer clean methods like start() without forcing the rest of your program to know the “how.”
3) Inheritance (Reuse and extend)
Inheritance allows one class to inherit fields/methods from another. This supports reuse and helps model relationships like “is-a.”
Beginner example:
If Truck is a type of Vehicle, then Truck can inherit basic vehicle behavior and add truck-specific features. Oracle’s OOP concept lesson includes inheritance as a core foundational concept.
4) Polymorphism (One interface, many forms)
Polymorphism lets you write code that works with a general type while executing the specific behavior of the actual object.
Beginner example:
If Vehicle has a method move(), then a Car and a Motorcycle can both implement move() differently. Your program can treat both as Vehicle, but each responds in its own way.
These four principles are often summarized as the “major principles” in beginner OOP resources.
Extra OOP “Design” Concepts You’ll Hear a Lot (Especially in Java)
Beyond the four pillars, many Java OOP explanations also emphasize:
Cohesion (keep a class focused on one job)
Coupling (avoid tightly dependent classes when possible)
Association / Aggregation / Composition (ways objects relate to each other)
These show up frequently in OOP concept roundups and become more important as projects get larger.
Why Employers Care (And Why I’m Blogging This)
From a career perspective, being able to explain concepts clearly is part of being a strong technical professional. OOP shows up everywhere: enterprise applications, Android, backend services, and large codebases where maintainability matters.
My Week 1 takeaway: Java setup can feel “extra” at first, but that structure pairs well with OOP. Once your tools are installed and you understand classes/objects, Java becomes much less intimidating and much more predictable.
Resources I Used (Beginner-Friendly)
Oracle Java Tutorials: Object-Oriented Programming Concepts
Eclipse Temurin (OpenJDK) Installation Guide
TutorialsPoint: Java OOP Concepts
“4 Major Principles of Object-Oriented Programming” (Lewallen reference copy)
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