現在遇到一個 linux 的 fd（開檔數量）過多造成的的系統問題。所以需要一個 java sample code 來 monitor current file.

Example Code below

import java.lang.management.ManagementFactory;
import java.lang.management.OperatingSystemMXBean;
import com.sun.management.UnixOperatingSystemMXBean;
public class OpenFileCount{
    public static
 
 void main(String[] args){
        OperatingSystemMXBean os = ManagementFactory.getOperatingSystemMXBean();
        if(os instanceof UnixOperatingSystemMXBean){
            System.out.println("Number of open fd: " + ((UnixOperatingSystemMXBean) os).getOpenFileDescriptorCount());
        }
    }
 

}