⚙️ Java Installation and First Project

Java Installation and First Project: Think of the JDK as connecting to the power grid, compiling a single file with `javac` as testing one outlet with a flashlight, and Maven as

Think of the JDK as connecting to the power grid, compiling a single file with `javac` as testing one outlet with a flashlight, and Maven as the breaker panel that manages the wiring of the whole house: first you confirm current flows through one outlet, then as the scale grows you manage everything from one panel — which is why the JDK comes on day 1 and Maven arrives once the need appears. But if IntelliJ can already write and run code, why do you also need a build tool like Maven? Because the IDE runs on your one machine, whereas Maven standardizes dependencies, versions, and build steps via `pom.xml` so they are identical for everyone. This is the Java equivalent of NuGet + MSBuild in the .NET world; compared to installing each package by hand with Python's `pip install`, Maven downloads everything deterministically in one command. For a QA engineer the difference is vital: pinning Selenium and JUnit5 versions in `pom.xml` makes your CI pipeline use the same jars on everyone's machine, eliminating version-driven false FAILs of the "passed for me, failed for you" kind.

🪟 Windows Installation

Windows — Install JDK 21 with winget

What Does winget Actually Do When Installing the JDK?

When winget install --id…

When `winget install --id EclipseAdoptium.Temurin.21.JDK` runs, Windows Package Manager finds and downloads the correct JDK 21 (LTS) installer from Microsoft's approved catalog.

The installer silently (no manual…

The installer silently (no manual clicking) unpacks the JDK files under `C:\Program Files\Eclipse Adoptium\`.

At this point the java/javac commands…

At this point the `java`/`javac` commands are NOT yet recognized in the terminal — the files exist on disk but are not on the PATH.

The next step (setting JAVA_HOME)…

The next step (setting JAVA_HOME) closes exactly this gap: it tells Windows "when you hear the java command, look here".

Output you should see:

Found Eclipse Temurin JDK 21 ... Successfully installed