Aug 17, 2010 11:23:26 PM dustin.examples.MapContainsGet generateStatesMapSEVERE: java.util.concurrent.ConcurrentHashMap does not allow for null values – java.lang ...

While the Hashtable was part of the initial Java release over two decades ago, the HashMap is the correct key-value store to use today. When Java 2 was released, the architects of the language ...