Summary

Bruce Eckel's Thinking in Java Contents | Prev | Next

To review the collections provided in the standard Java (1.0 and 1.1) library ( BitSet is not included here since it’s more of a special-purpose class):

  1. An array associates numerical indices to objects. It holds objects of a known type so you don’t have to cast the result when you’re looking up an object. It can be multidimensional, and it can hold primitives. However, its size cannot be changed once you create it.
  2. A Vector also associates numerical indices to objects – you can think of arrays and Vectors as random-access collections. The Vector automatically resizes itself as you add more elements. But a Vector can hold only Object handles, so it won’t hold primitives and you must always cast the result when you pull an Object handle out of a collection.
  3. A Hashtable is a type of Dictionary, which is a way to associate, not numbers, but objects with other objects. A Hashtable also supports random access to objects, in fact, its whole design is focused around rapid access.
  4. A Stack is a last-in, first-out (LIFO) queue.


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