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

In this quick tutorial on how the Java HashMap works internally, you'll learn the following aspects: The basic syntax of the Java HashMap. How keys, values, hash codes and node references interact.

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 ...