@Override
    protected boolean doStop() {
        if (null != this.channelFuture) {
            this.channelFuture.channel().close();
        }
        if (option(BoltServerOption.SERVER_SYNC_STOP)) {
            this.bossGroup.shutdownGracefully().awaitUninterruptibly();
        } else {
            this.bossGroup.shutdownGracefully();
        }
        if (option(BoltServerOption.SERVER_MANAGE_CONNECTION_SWITCH)
            && null != this.connectionManager) {
            this.connectionManager.shutdown();
            logger.warn("Close all connections from server side!");
        }
        for (UserProcessor<?> userProcessor : userProcessors.values()) {
            if (userProcessor.isStarted()) {
                userProcessor.shutdown();
            }
        }
        logger.warn("Rpc Server stopped!");
        return true;
    }
Notice: only RpcServer#option(BoltServerOption.SERVER_MANAGE_CONNECTION_SWITCH, true) switch on, will close all connections.

@see AbstractRemotingServer#doStop()
src/main/java/com/alipay/remoting/rpc/RpcServer.java