NoClassDefFoundError

Hi, All

My DC has dependency on the DC "tc/km/frwk", which has a reference to EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap;

When I was doing a local test, the following error was reported:java.lang.NoClassDefFoundError: EDU/oswego/cs/dl/util/concurrent/ConcurrentReaderHashMap.

Can anyone tell me where the class ConcurrentReaderHashMap is located?