jchmlib is a pure-Java CHM reader (no native code). It lists and reads files, parses the table of contents into a tree, searches with the CHM’s built-in full-text index, and detects the text encoding, which matters for Chinese, Japanese and Korean files. It also includes ChmWeb, a small web server for reading CHM files in a browser. Apache-2.0. The last release (0.5.4) is from 2017 and it’s only available from JitPack, not Maven Central.
jchmlibjchmlib is a pure-Java library for reading CHM (Compiled HTML Help) files. How to add it with Gradle or Maven, list files, read pages, extract a CHM.