The following test results in a NullPointerException (Linux only)

import java.net.*;
import java.nio.channels.*;

public class Test {
    public static void main(String[] args) throws Exception {
        DatagramChannel dc = DatagramChannel.open(StandardProtocolFamily.INET6)
            .setOption(StandardSocketOption.SO_REUSEADDR, true)
            .bind(new InetSocketAddress(0));
        InetAddress group = InetAddress.getByName("ff02::a");
        NetworkInterface ni = NetworkInterface.getByName("eth0");
        InetAddress source = InetAddress.getByName("::1");
        try {
            dc.join(group, ni, source);
        } catch (Exception x) { }

        dc.close();
    }
}

$ java Test
java.lang.NullPointerException
    at sun.nio.ch.MembershipRegistry.invalidateAll(MembershipRegistry.java:123)
    at sun.nio.ch.DatagramChannelImpl.implCloseSelectableChannel(DatagramChannelImpl.java:963)
    at java.nio.channels.spi.AbstractSelectableChannel.implCloseChannel(AbstractSelectableChannel.java:218)
    at java.nio.channels.spi.AbstractInterruptibleChannel.close(AbstractInterruptibleChannel.java:111)