public void forEach(BiConsumer<String, PluginType> consumer) {
            manifests.values().forEach(m -> forEach(m, consumer));
        }
A classpath workspace is backed by multiple jars, and is not writable.
The in-memory format is a map from jar path to the manifests contained in that jar.
The control flow of the caller should not perform writes, so these exceptions indicate a bug in the program.
tools/src/main/java/org/apache/kafka/tools/ManifestWorkspace.java