# Write files managed by `compiler` into concrete files
	fun write_java_files(compiler: JavaCompiler): Array[String] do
		var jfiles = new Array[String]
		for f in compiler.files do
			var filepath = "{compiler.compile_dir}/{f.filename}"
			var file = cache_file(filepath)
			for line in f.lines do file.write(line)
			close_cache(filepath, file)
			jfiles.add(f.filename)
		end
		return jfiles
	end