private void doJSCompression(final Reader in, Writer out, final String outputFilename) throws EvaluatorException, IOException {
traceVerbose("Start doJSCompression");
try {
// JS compressor
final JavaScriptCompressor compressor = new JavaScriptCompressor(in, new ErrorReporter() {
public void warning(final String message, final String sourceName,
final int line, final String lineSource, final int lineOffset) {
if (line < 0) {
trace(message);