title: Spring DM compatibility with Spring 4.*
body: <p>An OSGi based application I have inherited uses the org.springframework.osgi.extender bundle version 1.2.1.
  Currently, I am using Java 1.7 and Spring 2.5.6.</p>
  
  <p>I recently installed Java 8 on my machine and the org.springframework.osgi.extender bundle no longer launches due to the following error :</p>
  
  <pre><code>org.osgi.framework.BundleException: Activator start error in bundle org.springframework.osgi.extender [21].
          at org.apache.felix.framework.Felix.activateBundle(Felix.java:2196)
          at org.apache.felix.framework.Felix.startBundle(Felix.java:2064)
          at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:955)
          at org.apache.felix.shell.impl.StartCommandImpl.execute(StartCommandImpl.java:114)
          at org.apache.felix.shell.impl.Activator$ShellServiceImpl.executeCommand(Activator.java:249)
          at org.apache.felix.shell.tui.Activator$ShellTuiRunnable.run(Activator.java:184)
          at java.lang.Thread.run(Unknown Source)
  Caused by: java.lang.IllegalStateException: Cannot create ConcurrentHashMap - neither JDK 1.5 nor backport-concurrent available on the classpath
          at org.springframework.core.CollectionFactory.createConcurrentMap(CollectionFactory.java:229)
          at org.springframework.osgi.extender.internal.activator.ContextLoaderListener.&lt;init&gt;(ContextLoaderListener.java:332)
          at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
          at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
          at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
          at java.lang.reflect.Constructor.newInstance(Unknown Source)
          at java.lang.Class.newInstance(Unknown Source)
          at org.apache.felix.framework.Felix.createBundleActivator(Felix.java:4336)
          at org.apache.felix.framework.Felix.activateBundle(Felix.java:2141)
          ... 6 more
  java.lang.IllegalStateException: Cannot create ConcurrentHashMap - neither JDK 1.5 nor backport-concurrent available on the classpath
  </code></pre>
  
  <p>I was going to upgrade Spring to 4.0.3, but I notice that the org.springframework.core.CollectionFactory.createConcurrentMap() method has been deprecated and removed.</p>
  
  <p>Will Spring DM be upgraded to work with Spring 4.*?</p>