@Path("res/{path:.*}")
	@GET
	public Response webjars(@PathParam("path") String path, @HeaderParam("Accept-Encoding") String acceptEncoding) {

        // Guesses MIME type from the path extension elsewhere.
		String mime = mimes.getContentType(path);

		if (acceptEncoding.contains("gzip")) {
			InputStream is = getClass().getResourceAsStream("/META-INF/resources/webjars/" + path + ".gz");
			if (is != null)
				return Response.ok().type(mime).encoding("gzip").entity(is).build();
		}

		InputStream is = getClass().getResourceAsStream("/META-INF/resources/webjars/" + path);
		if (is != null)
			return Response.ok().type(mime).entity(is).build();

		return Response.status(Status.NOT_FOUND).build();
	}

package org.jboss.resteasy.plugins.interceptors.encoding;

import java.io.IOException;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.util.zip.GZIPOutputStream;

import javax.annotation.Priority;
import javax.ws.rs.Priorities;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.WriterInterceptor;
import javax.ws.rs.ext.WriterInterceptorContext;

import org.jboss.resteasy.annotations.GZIP;
import org.jboss.resteasy.util.CommitHeaderOutputStream;

/**
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @version $Revision: 1 $
 */
@Provider
@Priority(Priorities.ENTITY_CODER)
public class GZIPEncodingInterceptor implements WriterInterceptor {
	public static class EndableGZIPOutputStream extends GZIPOutputStream {
		public EndableGZIPOutputStream(OutputStream os) throws IOException {
			super(os);
		}

		@Override
		public void finish() throws IOException {
			super.finish();
			def.end(); // make sure on finish the deflater's end() is called to
						// release the native code pointer
		}
	}

	public static class CommittedGZIPOutputStream extends CommitHeaderOutputStream {
		protected CommittedGZIPOutputStream(OutputStream delegate, CommitCallback headers) {
			super(delegate, headers);
		}

		protected GZIPOutputStream gzip;

		public GZIPOutputStream getGzip() {
			return gzip;
		}

		@Override
		public void commit() {
			if (isHeadersCommitted)
				return;
			isHeadersCommitted = true;
			try {
				// GZIPOutputStream constructor writes to underlying OS causing
				// headers to be written.
				// so we swap gzip OS in when we are ready to write.
				gzip = new EndableGZIPOutputStream(delegate);
				delegate = gzip;
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
	}

	@Override
	public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException {

		// Original code decides by inspecting the Content-Encoding header right here.
		boolean isGZIPAnnotated = false;
		for (Annotation annotation : context.getAnnotations())
			if (annotation instanceof GZIP) {
				isGZIPAnnotated = true;
				break;
			}

		if (isGZIPAnnotated) {

			OutputStream old = context.getOutputStream();
			// GZIPOutputStream constructor writes to underlying OS causing
			// headers to be written.
			CommittedGZIPOutputStream gzipOutputStream = new CommittedGZIPOutputStream(old, null);

			// Any content length set will be obsolete
			context.getHeaders().remove("Content-Length");
			context.getHeaders().add("Content-Encoding", "gzip");

			context.setOutputStream(gzipOutputStream);
			try {
				context.proceed();
			} finally {
				if (gzipOutputStream.getGzip() != null)
					gzipOutputStream.getGzip().finish();
				context.setOutputStream(old);
			}
			return;
		} else {
			context.proceed();
		}
	}
}