Descriptors.java

import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.StandardOpenOption;
import java.util.ArrayList;
import java.util.List;

/**
 * Prints the maximum number of files possible to open in your system
 *
 * @author Yahor Radtsevich
 */
class Descriptors {
    public static void main(String [] args) {
        List<OutputStream> oss = new ArrayList<>();
        int i = 0;
        try {
            for (; i < 20_000; i++) {
                OutputStream os = Files.newOutputStream(Files.createTempFile("temp" , ".txt"),
                        StandardOpenOption.DELETE_ON_CLOSE, StandardOpenOption.CREATE);
                oss.add(os);
                os.write(i);
            }
        } catch (IOException e) {
            System.out.println("The maximum number of open files appears to be " + i + "." +
                    "\nWe got the following exception while trying to create such number of files + 1:" +
                    "\n\t" + e);
        } finally {
            for (OutputStream os : oss) {
                try {
                    os.close();
                } catch (IOException e) {
                    System.out.println(e);
                }
            }
        }
    }
}