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/*
 * @test
 * @bug     4858522
 * @summary Basic unit test of UnixOperatingSystemMXBean.getMaxFileDescriptorCount()
 * @author  Steve Bohne
 * @requires os.family != "windows"
 *
 * @run main GetMaxFileDescriptorCount
 */

import com.sun.management.UnixOperatingSystemMXBean;
import java.lang.management.*;

public class GetMaxFileDescriptorCount {

    private static UnixOperatingSystemMXBean mbean =
        (UnixOperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();

    private static long       minCountForPass = 1;
    private static final long MAX_COUNT_FOR_PASS = Long.MAX_VALUE;

    public static void main(String args[]) throws Exception {

        long minCount = mbean.getOpenFileDescriptorCount();
        if (minCount > 0) {
            minCountForPass = minCount;
        }

        long count = mbean.getMaxFileDescriptorCount();

        System.out.println("Max file descriptor count: " + count);

        if (count < minCountForPass || count > MAX_COUNT_FOR_PASS) {
            throw new RuntimeException("Max file descriptor count " +
                                       "illegal value: " + count + " bytes " +
                                       "(MIN = " + minCountForPass + "; " +
                                       "MAX = " + MAX_COUNT_FOR_PASS + ")");
        }

        System.out.println("Test passed.");
    }
}
