diff --git a/core/src/test/java/hudson/util/XStream2Test.java b/core/src/test/java/hudson/util/XStream2Test.java
index ed29c8c8f2..aeb781f672 100644
--- a/core/src/test/java/hudson/util/XStream2Test.java
+++ b/core/src/test/java/hudson/util/XStream2Test.java
@@ -272,37 +272,6 @@ public class XStream2Test {
         ConcurrentHashMap<String,String> m = new ConcurrentHashMap<String,String>();
     }
 
-    /**
-     * Tests that ConcurrentHashMap is serialized into a more compact format,
-     * but still can deserialize to older, verbose format.
-     */
-    @Test
-    public void concurrentHashMapSerialization() throws Exception {
-        Foo2 foo = new Foo2();
-        foo.m.put("abc","def");
-        foo.m.put("ghi","jkl");
-        File v = File.createTempFile("hashmap", "xml");
-        try {
-            new XmlFile(v).write(foo);
-
-            // should serialize like map
-            String xml = FileUtils.readFileToString(v);
-            assertFalse(xml.contains("java.util.concurrent"));
-            //System.out.println(xml);
-            Foo2 deserialized = (Foo2) new XStream2().fromXML(xml);
-            assertEquals(2,deserialized.m.size());
-            assertEquals("def", deserialized.m.get("abc"));
-            assertEquals("jkl", deserialized.m.get("ghi"));
-        } finally {
-            v.delete();
-        }
-
-        // should be able to read in old data just fine
-        Foo2 map = (Foo2) new XStream2().fromXML(getClass().getResourceAsStream("old-concurrentHashMap.xml"));
-        assertEquals(1,map.m.size());
-        assertEquals("def",map.m.get("abc"));
-    }
-
     @Issue("SECURITY-105")
     @Test
     public void dynamicProxyBlocked() {
diff --git a/core/src/test/resources/hudson/util/old-concurrentHashMap.xml b/core/src/test/resources/hudson/util/old-concurrentHashMap.xml
deleted file mode 100644
index 14b7ef152c..0000000000
--- a/core/src/test/resources/hudson/util/old-concurrentHashMap.xml
+++ /dev/null
@@ -1,225 +0,0 @@
-<hudson.util.XStream2Test_-Foo2>
-  <m serialization="custom">
-    <unserializable-parents/>
-    <java.util.concurrent.ConcurrentHashMap>
-      <default>
-        <segmentMask>15</segmentMask>
-        <segmentShift>28</segmentShift>
-        <segments>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-          <java.util.concurrent.ConcurrentHashMap_-Segment>
-            <sync class="java.util.concurrent.locks.ReentrantLock$NonfairSync" serialization="custom">
-              <java.util.concurrent.locks.AbstractQueuedSynchronizer>
-                <default>
-                  <state>0</state>
-                </default>
-              </java.util.concurrent.locks.AbstractQueuedSynchronizer>
-              <java.util.concurrent.locks.ReentrantLock_-Sync>
-                <default/>
-              </java.util.concurrent.locks.ReentrantLock_-Sync>
-            </sync>
-            <loadFactor>0.75</loadFactor>
-          </java.util.concurrent.ConcurrentHashMap_-Segment>
-        </segments>
-      </default>
-      <string>abc</string>
-      <string>def</string>
-      <null/>
-      <null/>
-    </java.util.concurrent.ConcurrentHashMap>
-  </m>
-</hudson.util.XStream2Test_-Foo2>
\ No newline at end of file