How can I configure NFS (v3) lockd to work across multiple IP addresses?

Question

Consider the following short program, where /nfsmount/merlin is an NFS-mounted directory.

import java.io.*; 
import java.nio.channels.*; 

public class Main{ 
    public static void main(String[] args) throws Exception { 
        String evilFile = "/nfsmount/merlin/foobar"; 
        RandomAccessFile raf = new RandomAccessFile(evilFile, "rw"); 
        FileChannel chan = raf.getChannel(); 
        FileLock lock = chan.tryLock(); 
    } 
} 

The NFS server has two IP addresses. When it is mounted over the first IP, the program above works fine. However, when it is mounted over the second IP, the program gives the following error.

Exception in thread "main" java.io.IOException: No locks available
    at sun.nio.ch.FileDispatcherImpl.lock0(Native Method)
    at sun.nio.ch.FileDispatcherImpl.lock(FileDispatcherImpl.java:91)
    at sun.nio.ch.FileChannelImpl.tryLock(FileChannelImpl.java:1095)
    at java.nio.channels.FileChannel.tryLock(FileChannel.java:1154)
    at Main.main(Main.java:11)

A quick search leads to this question, which seems to indicate that there's something wrong with lockd. The fact that the program works on one IP would imply that lockd is only bound to one IP.

How can I configure it so that lockd works correctly over multiple IP's?