### Question:
Http2MultiplexCodecBuilder extends AbstractHttp2ConnectionHandlerBuilder<Http2MultiplexCodec, Http2MultiplexCodecBuilder> { public static Http2MultiplexCodecBuilder forServer(ChannelHandler childHandler) { return new Http2MultiplexCodecBuilder(true, childHandler); } Http2MultiplexCodecBuilder(boolean server, ChannelHandler childHandler); static Http2MultiplexCodecBuilder forClient(ChannelHandler childHandler); static Http2MultiplexCodecBuilder forServer(ChannelHandler childHandler); @Override Http2Settings initialSettings(); @Override Http2MultiplexCodecBuilder initialSettings(Http2Settings settings); @Override long gracefulShutdownTimeoutMillis(); @Override Http2MultiplexCodecBuilder gracefulShutdownTimeoutMillis(long gracefulShutdownTimeoutMillis); Http2MultiplexCodecBuilder withUpgradeStreamHandler(ChannelHandler upgradeStreamHandler); @Override boolean isServer(); @Override int maxReservedStreams(); @Override Http2MultiplexCodecBuilder maxReservedStreams(int maxReservedStreams); @Override boolean isValidateHeaders(); @Override Http2MultiplexCodecBuilder validateHeaders(boolean validateHeaders); @Override Http2FrameLogger frameLogger(); @Override Http2MultiplexCodecBuilder frameLogger(Http2FrameLogger frameLogger); @Override boolean encoderEnforceMaxConcurrentStreams(); @Override Http2MultiplexCodecBuilder encoderEnforceMaxConcurrentStreams(boolean encoderEnforceMaxConcurrentStreams); @Override Http2HeadersEncoder.SensitivityDetector headerSensitivityDetector(); @Override Http2MultiplexCodecBuilder headerSensitivityDetector(
            Http2HeadersEncoder.SensitivityDetector headerSensitivityDetector); @Override Http2MultiplexCodecBuilder encoderIgnoreMaxHeaderListSize(boolean ignoreMaxHeaderListSize); @Override Http2MultiplexCodecBuilder initialHuffmanDecodeCapacity(int initialHuffmanDecodeCapacity); @Override Http2MultiplexCodec build();  }### Answer:
@Test public void testSharableCheck() { assertNotNull(Http2MultiplexCodecBuilder.forServer(new SharableChannelHandler1())); assertNotNull(Http2MultiplexCodecBuilder.forServer(new SharableChannelHandler2())); }
@Test(expected = IllegalArgumentException.class) public void testUnsharableHandler() { Http2MultiplexCodecBuilder.forServer(new UnsharableChannelHandler()); }