Foundation
Setting Up Java
Install it, run it by hand, understand what you installed.
Which JDK to install and why there are so many, what JAVA_HOME and PATH actually decide, and a first program you compiled and ran yourself rather than clicked a button on. Short, practical, and the reason nothing later says "it works on my machine".
8 lessons written3 modules~1h reading
After this course you can
- Choose a JDK distribution and version deliberately rather than by accident
- Install one and prove which java and javac are running
- Compile and run a program from the command line, and read the errors when it fails
- Explain why a class in a package must be run by its full name
- Use JShell to try a line of Java without writing a class
Curriculum
8 lessons · outlined lessons show their plan01
Java, and which JavaWhere the language came from, what its original promises still mean, why one class file runs on any machine, what SE and Jakarta EE are, and why the version numbers jump around.12 minChoosing a JDK: distribution and versionTemurin, Corretto, Zulu, Oracle — the same code with different support. And what LTS buys you.10 minWhich Java, and why there are so many
02
Installing a JDK, and JAVA_HOMEInstalling one, then proving which one you got — and the two variables that decide it.12 minjavac and java, by handCompiling and running without an IDE, the errors each step produces, and the source launcher that skips the first step.14 minJShell: Java without the ceremonyA line of Java with no class, no main and no compile step — the fastest way to check what something does.8 minGetting it on your machine
03
main, and the arguments it is handedWhy the signature is exactly that, what the JVM passes you, and what the shell did to it first.10 minPackages, directories and where classes goWhy a packaged class must be run by its full name, and what -d is for.12 minSetting up an IDE for JavaPointing it at the JDK you chose, and the three settings worth changing on day one.8 min