protected Proto searchFromProtoPathAndClasspath(String path, Proto importer)
            throws Exception
    {
        // proto_path
        File protoFile;
        for (File dir : __protoLoadDirs)
        {
            if ((protoFile = new File(dir, path)).exists())
                return loadFrom(protoFile, importer);
        }

        // classpath
        Proto protoFromOtherResource = loadFromOtherResource(path, importer);
        if (protoFromOtherResource == null)
        {
            throw new IllegalStateException("Imported proto " + path +
                    " not found. (" + importer.getSourcePath() + ")");
        }

        return protoFromOtherResource;
    }
Search from proto_path and classpath (in that order).
<p>

<pre>
Enable via:
-Dproto_path=$path -Dproto_search_strategy=2
</pre>
protostuff-parser/src/main/java/io/protostuff/parser/DefaultProtoLoader.java