Java 8 (64-Bit 1.8.0) for Minecraft 1.7.10, 1.12.2 & 1.16.5

Older Forge versions on 1.7.10, 1.12.2, and 1.16.5 rely on Java 8 reflection internals and will crash with Exit Code 1 if launched on Java 17 or Java 21. Applies to Minecraft 1.1 – 1.16.5.

Configuration

Java 8 (64-Bit 1.8.0) for Minecraft 1.7.10, 1.12.2 & 1.16.5

Minecraft Range

Minecraft 1.1 – 1.16.5

Recommended Build

Eclipse Adoptium Temurin 8 (x64)

JVM Flags

-XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:G1ReservePercent=20

Why Java 8 (64-Bit 1.8.0) for Minecraft 1.7.10, 1.12.2 & 1.16.5 matters for Minecraft 1.1 – 1.16.5

Older Forge versions on 1.7.10, 1.12.2, and 1.16.5 rely on Java 8 reflection internals and will crash with Exit Code 1 if launched on Java 17 or Java 21.

Inside Prism Launcher, open **Settings** → **Java** (or override per instance under **Edit Instance** → **Settings**) and click **Auto-detect** or **Download** to select `Eclipse Adoptium Temurin 8 (x64)`.

Recommended JVM flags and memory checks

• **JVM arguments:** `-XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:G1ReservePercent=20`. Always click **Test** in the Java settings panel to verify the runtime passes Prism's architecture check.
• **64-bit verification:** Ensure the architecture column reads `x86_64` (or `arm64`), never 32-bit `x86`, so you can allocate more than 2 GB of RAM.
• **Download launcher:** Get the latest Windows build of Prism Launcher from /download.