title: Guava Duplicate keys exception IllegalArgumentException
body: <p>Here is a quick snipped. </p>
  
  <pre><code>Map&lt;String, String&gt; map = new HashMap&lt;String, String&gt;();
  map.put("1", "1");
  map.put("2", "1");          
  Ordering&lt;String&gt; valueComparator = Ordering.from(String.CASE_INSENSITIVE_ORDER).onResultOf(Functions.forMap(map));  
  Map&lt;String, String&gt; sortedMap = ImmutableSortedMap.copyOf(map, valueComparator);
  </code></pre>
  
  <p>When i run it i get this exception. </p>
  
  <pre><code>java.lang.IllegalArgumentException: Duplicate keys in mappings 2=1 and 1=1
      at com.google.common.collect.ImmutableSortedMap.validateEntries(ImmutableSortedMap.java:304)
      at com.google.common.collect.ImmutableSortedMap.copyOfInternal(ImmutableSortedMap.java:281)
      at com.google.common.collect.ImmutableSortedMap.copyOf(ImmutableSortedMap.java:220)
      at com.dbs.datasource.TestBeans.test(TestBeans.java:90)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at junit.framework.TestCase.runTest(TestCase.java:168)
      at junit.framework.TestCase.runBare(TestCase.java:134)
      at org.springframework.test.ConditionalTestCase.runBare(ConditionalTestCase.java:76)
      at junit.framework.TestResult$1.protect(TestResult.java:110)
      at junit.framework.TestResult.runProtected(TestResult.java:128)
      at junit.framework.TestResult.run(TestResult.java:113)
      at junit.framework.TestCase.run(TestCase.java:124)
      at junit.framework.TestSuite.runTest(TestSuite.java:243)
      at junit.framework.TestSuite.run(TestSuite.java:238)
      at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83)
      at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
      at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
  </code></pre>
  
  <p>It looks like it swapping key and value somewhere. Using guava-14.0-rc1.jar</p>