A Programmer[ap]s Guide to Java Certification

Make appropriate selection of collection classes/interfaces to suit specified behavior requirements.

Distinguish between correct and incorrect implementations of hashCode() (and equals() ) methods .

Identify the core collection interfaces and their inheritance relationships: Collection , Set , SortedSet , List , Map , SortedMap .

Understand the differences between collections and maps.

Understand the operations performed by the addAll() , removeAll() , and retainAll() methods in the Collection interface.

Recognize destructive and non-destructive collection operations.

Understand how data can be passed between collections.

Identify the implementations of the core collection interfaces and state their usage: HashSet , TreeSet , LinkedHashSet , ArrayList , Vector , LinkedList , HashMap , Hashtable , TreeMap , LinkedHashMap .

Write code to create views on collections.

Use an iterator to traverse all the elements of a collection.

Distinguish between unordered, ordered, and sorted collections.

Understand the natural ordering of elements provided by the Comparable interface and the total ordering imposed by the Comparator interface.

State the conditions under which an UnsupportedOperationException may occur in collections.

Identify the methods in the Collections class that can be used to produce immutable and thread-safe versions of various types of collections.

State the major algorithms provided by the Collections class.

Write code to pass data between arrays and collections.