Pattern: Use of Hashtable
Issue: -
Checks for references to the (effectively) obsolete java.util.Hashtable class. Use the Java Collections Framework classes instead, including HashMap or ConcurrentHashMap. See the JDK javadoc.
Note: As of the Java 2 platform v1.2, this class was retrofitted to implement the Map interface, making it a member of the Java Collections Framework. Unlike the new collection implementations, Hashtable is synchronized. If a thread-safe implementation is not needed, it is recommended to use HashMap in place of Hashtable. If a thread-safe highly-concurrent implementation is desired, then it is recommended to use ConcurrentHashMap in place of Hashtable.
Example of violations:
def someMap = new Hashtable() // violation