ADDITIONAL SYSTEM INFORMATION :
OS:
Red Hat Linux 7.4 Linux 3.10.0-693.el7.x86_64 #1 SMP

Java:
openjdk version "14-ea" 2020-03-17
OpenJDK Runtime Environment (build 14-ea+20-879)
OpenJDK 64-Bit Server VM (build 14-ea+20-879, mixed mode, sharing)

A DESCRIPTION OF THE PROBLEM :
JDK-7118373 is fixed for SocketChannel in JDK8, but is not fixed for SctpChannel in latest
JDK release (JDK 14-ea+20).


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Run test case as background process.
  java ESctp &
2. Repleat to invoke "lsof -U -a -p [PID]" during running above process

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Number of unix socket keeps 1
ACTUAL -
Number of unix socket increases linearly

---------- BEGIN SOURCE ----------
import java.net.*;
import java.util.*;
import java.io.*;
import java.nio.channels.*;
import com.sun.nio.sctp.*;

class ESctp
{
  static Selector selector;
  static int NUM = 10;
  static SelectorThread selthread;

  public static void main(String[] args) throws Exception
  {
    int port = 12345;

    if (!isSCTPSupported()) {
      System.out.println("SCTP protocol is not supported");
      System.out.println("Test cannot be run");
      return;
    }

    if (args.length == 1) {
      try {
        port = Integer.parseInt(args[0]);
      } catch(Exception e) {}
    }
    new Server(port).start();

    new Server2(port+1).start();
    Thread.sleep(100); // wait for server ready
    selector = Selector.open();

    init(port+1);

    selthread = new SelectorThread();
    selthread.start();

    for (int i = 0 ; i < 500 ; ++i) {
      System.out.println(i);
      doIt(port);
      Thread.sleep(200);
    }
    System.out.println("end");
    System.exit(0);
  }

  static boolean isSCTPSupported() {
    try {
      SctpChannel c = SctpChannel.open();
      c.close();
      return true;
    } catch (IOException ioe) {
      ioe.printStackTrace();
    } catch (UnsupportedOperationException e) {
      System.out.println(e);
    }

    return false;
  }

  static void init(int port) throws Exception
  {
    InetSocketAddress sa = new InetSocketAddress("localhost", port);
    for (int i = 0 ; i < 3 ; ++i) {
      SctpChannel channel = SctpChannel.open(sa, 1, 1);
      channel.configureBlocking(false);
      channel.register(selector, SelectionKey.OP_READ);
    }
  }


  static void doIt(int port) throws Exception
  {
    InetSocketAddress sa = new InetSocketAddress("localhost", port);

    for (int i = 0 ; i < NUM ; ++i) {
      System.out.println(" " + i);
      SctpChannel channel = SctpChannel.open(sa, 1, 1);
      channel.configureBlocking(false);

      SelectionKey key = selthread.regchannel(channel);

      key.cancel();
      selector.wakeup();
      channel.close();

      Thread.sleep(200);
    }
  }

  static class SelectorThread extends Thread
  {
    Object lock = new Object();
    SctpChannel channel;
    SelectionKey key;

    SelectionKey regchannel(SctpChannel ch) throws Exception
    {
      synchronized (lock) {
channel = ch;
selector.wakeup();
lock.wait();
      }
      return key;
    }

    public void run()
    {
      try {
        while (true) {
selector.select(10000);
synchronized (lock) {
if (channel != null) {
key = channel.register(selector, SelectionKey.OP_READ);
channel = null;
lock.notify();
}
}
        }

      } catch (Exception e) {
e.printStackTrace();
      }
    }
  }

  static class Server2 extends Thread
  {
    SctpChannel[] x;
    int port;

    Server2(int port) {
      this.port = port;
    }

    public void run()
    {
      x = new SctpChannel[32];
      int i = 0;
      try {
SctpServerChannel ss = SctpServerChannel.open();
InetSocketAddress sa = new InetSocketAddress("localhost", port);
ss.bind(sa);
while (true) {
SctpChannel soc = ss.accept();
          x[i] = soc;
          i++;
}
      } catch (Exception e) {
e.printStackTrace();
      }
    }
  }
    
  static class Server extends Thread
  {
    int port;

    Server(int port) { this.port = port; }

    public void run()
    {
      try {
SctpServerChannel ss = SctpServerChannel.open();
InetSocketAddress sa = new InetSocketAddress("localhost", port);
ss.bind(sa);
while (true) {
SctpChannel soc = ss.accept();
soc.close();
}
      } catch (Exception e) {
e.printStackTrace();
      }
    }
  }
}


---------- END SOURCE ----------

FREQUENCY : rarely