Java Queue Questions (122)

1. How does a PriorityQueue order its elements?
   
   Answer: A PriorityQueue orders its elements using a user-defined priority?

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2. Which interface does a PriorityQueue implement to impose an ordering other than “natural ordering”?
   
   Answer:
   The Comparator interface.

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3. What does the T[] syntax represent?
   
   Answer: This syntax represents an array that is not an array of primitives.

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4. Can the Iterator interface be used with the Map interface?
   
   Answer: No. The Iterator interface will get an Iterator for a List or a Set.

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5. What are the relative positions of uppercase characters, lowercase characters, and spaces in a natural ordering?
   
   Answer: Spaces sort before characters and uppercase letters sort before lowercase characters.

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6. What is the difference between NavigableSet and NavigableMap interfaces?
   
   Answer:
   NavigableSet<E> inherits from Iterable<T> .
   NavigableMap<K,V> inherits from Map<K,V> .

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7. Why were Generics added to the Java language?
   
   Answer: Collections are the overwhelming reason and motivation for adding generics to the language.

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8. Can you integrate Java 5 and Java 6 generic code with legacy non-generic code?
   
   Answer: Yes, but most of the errors will occur at run time

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9. How many ways can we track client and what are they?
   
   Answer:
   The servlet API provides two ways to track client state and they are:
   1. Using Session tracking and
   2. Using Cookies.

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10. What is a characteristic of a non-generic collection?
    
    Answer:
    A non-generic collection can hold any kind of object. A non-generic collection is quite happy to hold anything that is NOT a primitive.