🗑️ What Happened to the JRE?
Before Java 11
- You could download either: ✅ JDK (for development)
✅ JRE (for just running programs — without compiler/tools)
Starting with Java 11 (released in 2018)
- The standalone JRE package was removed.
- Now, only the JDK is available for download.
- The JDK itself still contains everything you need to run programs (including the JVM and core libraries), so the JDK essentially includes the JRE functionality.
- But there’s no separate “JRE download” anymore.
🔗 Why Was JRE Removed?
The main reasons:
1️⃣ To simplify the packaging — Having separate JDK and JRE was confusing to many developers.
2️⃣ Many users were installing the JDK anyway, even if they only needed to run programs (because some apps/tools require development tools like javac).
3️⃣ Modularization (introduced in Java 9) — With the Java Platform Module System (JPMS), the concept of “runtime environment” became more flexible (you can even create your own minimal runtime using jlink).
🚀 What This Means for You
| Situation | What to Do Now |
|---|---|
| You need to run a program (not develop) | Just install the JDK. It contains everything (JVM + libraries). |
| You need to develop | Install the JDK (same as before). |
| You want a smaller runtime for distribution | Use jlink (part of JDK 9+) to generate a custom runtime image containing only the modules your app needs. |
🔔 Key Takeaway
✅ Starting from Java 11, you no longer need to think about JRE vs JDK.
✅ Just install the JDK and you’re covered — for both running and developing.