Use of obsolete collection type

Reports usages of java.util.Vector, java.util.Hashtable and java.util.Stack.

Usages of these classes can often be replaced with usages of java.util.ArrayList, java.util.HashMap and java.util.ArrayDeque respectively. While still supported, the former classes were made obsolete by the JDK1.2 collection classes, and should probably not be used in new development.

Use the Ignore obsolete collection types where they are required option to ignore any cases where the obsolete collections are used as method arguments or assigned to a variable that requires the obsolete type. Enabling this option may consume significant processor resources.