Asynchronous Future Parallel processing request code example

The thread pool is implemented in cooperation with future, but the main request thread is blocked. High concurrency will still cause too many threads. CPU context switching. Through future, n requests can be sent concurrently, and then wait for the slowest return. The total response time is the time returned by the slowest request

public class Test{
  final static ExecutorService executor = Executors.newFixedThreadPool(2);

  public static void main(String[] args){
    RpcService rpcService = new RpcService();
    HttpService httpService = new HttpService();
    Future<Map<String,String>> future1 = null;
    Future<Integer> future2 = null;
      future1 = executor.submit(()->rpcService.getRpcResult());
      future2 = executor.submit(()->httpService.getHttpResult());
    }catch(Exception e){
       if(future1 != null){
       if(future2 != null){
       throw new RuntimeEException(e);
  static class RpcService{
    Map<String,String> gerRpcResult() throws Exception{
      //Calling remote methods, taking 10ms

  static class HttpService{
    Integer getHttpResult() throws Exception{
      //Calling remote methods, taking 30ms

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