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Forge’s Java Dance: A Guide to Picking the Right Version

Choosing the right Java version for Forge is a crucial step in getting your Minecraft modding adventure off the ground. It’s not a one-size-fits-all answer, as the Forge version and Minecraft version you’re targeting dictate the Java version you need. Here’s the breakdown:

Minecraft 1.18 and higher (including 1.19, 1.20, and beyond): You absolutely need Java 17. This is non-negotiable.
Minecraft 1.17.x: Java 16 is your go-to.
Minecraft 1.16.5: While Java 16 can work, Java 8 is generally the most stable and recommended option.
Minecraft 1.12 to 1.16.4: Java 8 (1.8.0 or newer) is the standard.
Minecraft versions before 1.12: Generally, Java 8 or earlier is required, but it’s best to consult the specific Forge documentation for those older versions.

It’s vital to understand that using the wrong Java version can lead to crashes, errors, and a generally frustrating experience. This guide dives deep into the intricacies of Java versions and Forge, helping you navigate the sometimes-confusing landscape of Minecraft modding. The GamesLearningSociety.org has great research and resources on using games for learning that may further aid you in your modding adventure!

Why Does Java Matter for Forge?

Minecraft, at its core, is a Java application. Forge, as a modding framework, is also built on Java. Therefore, Forge depends on a Java Runtime Environment (JRE) to execute.

Compatibility: Different Minecraft versions use different versions of Java’s bytecode. Forge needs to be compiled against the same bytecode for things to work. Newer versions of Minecraft are coded with newer version of Java.
Libraries and Dependencies: Forge and mods rely on external Java libraries that must be compatible with the Java version you’re using.
Performance: Using the correct Java version can also affect the game’s performance. Older versions of Java might not be as optimized for newer Minecraft versions.

Understanding JDK vs. JRE

Before we dive deeper, let’s clarify the difference between the Java Development Kit (JDK) and the Java Runtime Environment (JRE).

JDK (Java Development Kit): This is the complete package you need if you plan to develop Java applications (like creating mods). It includes the JRE, compilers, debuggers, and other tools.
JRE (Java Runtime Environment): This is what you need to run Java applications (like playing Minecraft with Forge). It includes the Java Virtual Machine (JVM) and core Java libraries.

For simply playing Minecraft with Forge, you technically only need the JRE. However, Forge often recommends having the JDK installed, especially if you plan to do any kind of mod development or configuration. The JDK includes the JRE.

Selecting the Right Java Distribution

Several Java distributions are available, each with its own strengths and weaknesses. Here are a couple of popular ones that Forge recommends:

Eclipse Temurin (formerly AdoptOpenJDK): This is a free, open-source distribution of Java based on OpenJDK. Forge often officially supports Temurin because it is stable, reliable, and community-driven.
Oracle JDK: This is the official Java distribution from Oracle. While it offers commercial support, it’s also available for free under certain licenses. Be aware of the licensing terms, as they have changed over time.

OpenJDK is the foundation of both Temurin and Oracle JDK. Choosing between them often comes down to personal preference and licensing considerations.

How to Check Your Java Version

Open a Command Prompt (Windows) or Terminal (macOS/Linux).
Type java -version and press Enter.

The output will show you the Java version you have installed.

Troubleshooting Java-Related Forge Issues

If Forge isn’t working correctly, here are some troubleshooting steps:

Verify the Java version: Double-check that you have the correct Java version installed for your Forge/Minecraft version.
Check the Java path: Ensure that the Java executable is in your system’s PATH environment variable. This allows Forge to find Java.
Reinstall Java: Sometimes, a corrupted Java installation can cause problems. Try uninstalling and reinstalling Java.
Adjust launcher settings: Some Minecraft launchers allow you to specify which Java version to use. Make sure it’s pointing to the correct one.
Consult Forge logs: Check the Forge logs for any error messages that might indicate a Java-related issue.

Frequently Asked Questions (FAQs)

Here are 15 frequently asked questions to further illuminate the relationship between Forge and Java:

Do I need both JDK and JRE for Forge? No, you technically only need the JRE to run Forge. However, the JDK is recommended, especially if you plan to create mods or configure them beyond basic settings. The JDK comes bundled with the JRE.
Can I use a newer Java version than the one recommended for Forge? While it might work in some cases, it’s generally not recommended. Newer Java versions might introduce incompatibilities that can cause crashes or unexpected behavior. Stick to the recommended version for the best stability.
How do I install a specific version of Java? Download the installer for the desired Java version from the official website of your chosen distribution (e.g., Eclipse Temurin or Oracle). Follow the installation instructions, ensuring you choose the correct architecture (64-bit).
I have multiple Java versions installed. How do I make Forge use the correct one? This depends on your Minecraft launcher. Many launchers allow you to specify the Java executable to use in the launcher settings. Ensure this points to the correct Java version for your Forge installation.
Forge is crashing with a “java.lang.UnsupportedClassVersionError”. What does this mean? This error indicates that you’re using an incompatible Java version. The class file was compiled with a newer version of Java than your JRE can understand. Make sure you are using the correct Java version for your version of Forge.
Does Forge support Java 18, 19, 20, or 21? As of the current time (October 26, 2023), Forge is typically aligned with the Long-Term Support (LTS) Java releases. While it’s technically possible to use newer versions, it’s best to stick with the officially supported Java version (Java 17 for newer Minecraft versions) for maximum compatibility.
Do I need to uninstall older Java versions if I install a newer one? It’s generally recommended to uninstall older Java versions to avoid potential conflicts. However, this is a matter of preference and some users find it useful to keep old versions around for compatibility with other programs that require them. If you choose to keep older versions, ensure you configure your launcher to use the appropriate Java version for Forge.
Why does Forge recommend Eclipse Temurin? Eclipse Temurin is a reliable, open-source distribution of Java that’s well-maintained and free to use. Its compatibility and stability make it a popular choice within the Minecraft modding community.
Is there a performance difference between different Java distributions for Forge? Performance differences are usually minimal between different OpenJDK-based distributions (like Eclipse Temurin and Oracle JDK). The more significant factor is using the correct Java version for your Forge/Minecraft setup.
My Forge installer isn’t opening. What can I do? Make sure you have the correct Java version installed. You also need to download the .JAR file. Right-click the jar, go to properties, and check “Opens With”. Make sure it is set to Java.
Does Java impact mod compatibility? Yes, Java’s version significantly impacts mod compatibility. Mods compiled using a certain Java version will likely be incompatible with a Minecraft and Forge setup using a drastically different Java version.
What is Java Edition? Java Edition is one of the versions of Minecraft that you can mod using Forge. To mod, you must be using Java Edition.
What can I use instead of Eclipse Temurin? OpenJDK, Zulu, and Oracle JDK are all other versions you can use. Make sure the one you pick has the Java version your setup requires.
What happens if my Java is too old? Minecraft will either fail to load the game or you’ll receive constant crashes and errors that don’t allow you to play.
Can I run mods without Forge? No, you cannot. Forge is the software needed to run mods.

By following these guidelines and troubleshooting tips, you can ensure that you have the correct Java version installed and configured for your Forge installation, leading to a smoother and more enjoyable Minecraft modding experience. Happy modding!

What version of Java does forge require?