Gemma4.java: Run Gemma 4 in pure Java (no Python, no JNI)

I built llama3.java in the past, this is a follow-up: Gemma 4 running entirely on the JVM.

No Python. No JNI. No native code. Just Java.

It’s (mostly) a single Java file implementing the full stack:

GGUF parsing, tokenization, Gemma 4 transformer inference, quantizations, CLI...

Built using the Java Vector API, with support for GraalVM Native Image.