### Question:
Bootstrap implements ExternalResourceReleasable { public void setOption(String key, Object value) { if (key == null) { throw new NullPointerException("key"); } if (value == null) { options.remove(key); } else { options.put(key, value); } } protected  Bootstrap(); protected  Bootstrap(ChannelFactory channelFactory); ChannelFactory getFactory(); void setFactory(ChannelFactory factory); ChannelPipeline getPipeline(); void setPipeline(ChannelPipeline pipeline); Map<String, ChannelHandler> getPipelineAsMap(); void setPipelineAsMap(Map<String, ChannelHandler> pipelineMap); ChannelPipelineFactory getPipelineFactory(); void setPipelineFactory(ChannelPipelineFactory pipelineFactory); Map<String, Object> getOptions(); void setOptions(Map<String, Object> options); Object getOption(String key); void setOption(String key, Object value); void releaseExternalResources(); void shutdown();  }### Answer:
@Test(expected = NullPointerException.class) public void shouldNotAllowNullOptionKeyOnSet() { newBootstrap().setOption(null, "x"); }