1. | What’s the purpose of the Java collections framework? |
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2. | Into what four primary areas is the Java collections framework organized? |
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3. | What are the six core collection interfaces offered in the Java platform version 1.4.2 collections framework? |
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4. | Describe the performance characteristics of a linked list. |
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5. | Describe the performance characteristics of a hashtable. |
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6. | Describe the performance characteristics of a red-black tree. |
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7. | What’s the purpose of an Iterator? |
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8. | Describe the fundamental differences between the Java 5 collections framework and previous collections framework versions. |
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9. | What’s the difference between an Iterator and a ListIterator? |
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10. | When would you chose to iterate over the elements of a Java 5 collection using the enhanced for loop vs. an ordinary for loop and an Iterator? |
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Answers
1. | - Provides a comprehensive API for collections management. Java developers learn one API and their collection manipulation code is guaranteed to work across deployment platforms. |
2. | - interfaces, implementation classes, algorithms, infrastructure |
3. | -Collection, List, Set, SortedSet, Map, SortedMap |
4. | - List elements can reside anywhere in memory and are accessed via next and previous pointers. |
5. | - Elements are inserted into position according to an object’s hashcode. Object’s with the same hashcode will be appended to a linked list at the element position. |
6. | - A red-black tree is self-sorting and self-balancing. Leaf nodes are always the same number of black nodes away from the root element. |
7. | - Allows you to remove elements from a collection using the remove() method. |
8. | - Java 5 collections introduced generics and several new interface and implementation classes. The enhanced for loop enables you to iterate over a collection without explicitly declaring and using an Iterator. |
9. | - An iterator moves forward through a collection’ s elements; a ListIterator moves forward and backward. |
10. | - When you don’t want to remove elements from the collection. |