3 ms·
https://github.com/openjdk/jdk/tree/master/src/jdk.compiler/share/classes/com/sun/tools/javac https://github.com/openjdk/jdk/tree/master/src/jdk.compiler/...,
by hyperpape 3y ago
https://github.com/openjdk/jdk/tree/master/src/jdk.compiler/share/classes/com/sun/tools/javac https://github.com/openjdk/jdk/tree/master/src/jdk.compiler/...,
Wiki citation for good measures https://en.wikipedia.org/wiki/Javac https://en.wikipedia.org/wiki/Javac.
Maybe you're thinking of Hotspot, which is written in C++.