# Packages, JARs & Build Tools — Core Java

Source: https://www.geekswithgeeks.com/en/core-java/java-packages-build

> Organise code into packages, understand the classpath, and build a runnable JAR with Maven or Gradle before moving on to Advanced Java.

## Packages & classpath

A `package com.acme.orders;` declaration maps to a folder path and namespaces your classes. The **classpath** tells the JVM where to find compiled classes and library JARs at runtime.

## Maven / Gradle

Real projects use a build tool to fetch dependencies, compile, test, and produce a JAR. You declare dependencies once; the tool resolves the graph.

```bash
mvn package        # Maven: compile + test + build target/*.jar
./gradlew build    # Gradle equivalent
java -jar target/app-1.0.jar
```

## Where to next

With the fundamentals solid, move on to **Advanced Java**: generics in depth, lambdas and streams, concurrency, JDBC, and frameworks like Spring.