code: package io.ray.serve.util;
  
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.net.ServerSocket;
  
  public class SocketUtil {
  
    public static final int PORT_RANGE_MAX = 65535;
  
    public static int findAvailableTcpPort(int minPort) {
      int portRange = PORT_RANGE_MAX - minPort;
      int candidatePort = minPort;
      int searchCounter = 0;
      while (!isPortAvailable(candidatePort)) {
        candidatePort++;
        if (++searchCounter > portRange) {
          throw new IllegalStateException(
              String.format(
                  "Could not find an available tcp port in the range [%d, %d] after %d attempts.",
                  minPort, PORT_RANGE_MAX, searchCounter));
        }
      }
      return candidatePort;
    }
  
    public static boolean isPortAvailable(int port) {
      ServerSocket socket;
      try {
        socket = new ServerSocket();
      } catch (IOException e) {
        throw new IllegalStateException("Unable to create ServerSocket.", e);
      }
  
      try {
        InetSocketAddress sa = new InetSocketAddress(port);
        socket.bind(sa);
        return true;
      } catch (IOException ex) {
        return false;
      } finally {
        try {
          socket.close();
        } catch (IOException ex) {
          // ignore this exception for now
        }
      }
    }
  }
  