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collection framework in java
1. What is the Collection Framework in Java?
Answer: The Collection Framework in Java is a set of classes and interfaces that provide a unified way to manage groups of objects. It is used to store, manipulate, and retrieve collections of objects.
2. What are the benefits of using the Collection Framework in Java?
Answer: The benefits of using the Collection Framework in Java include:
It provides a unified architecture for managing groups of objects.
It provides a set of reusable data structures and algorithms.
It improves code reusability and makes code more readable.
It provides high-performance implementations of data structures such as ArrayList, HashMap, etc.
3. What is the difference between a Set and a List in Java?
Answer: The main difference between a Set and a List in Java is that a Set is an unordered collection of objects that does not allow duplicates, whereas a List is an ordered collection of objects that allows duplicates.
4. What is an Iterator in Java?
Answer: An Iterator in Java is an object that allows you to traverse a collection of objects and access its elements in a sequential manner.
5. What is the difference between an ArrayList and a LinkedList in Java?
Answer: The main difference between an ArrayList and a LinkedList in Java is that an ArrayList uses an array to store its elements, while a LinkedList uses a doubly-linked list to store its elements. As a result, an ArrayList is faster for accessing elements by their index, while a LinkedList is faster for adding or removing elements from the middle of the list.
6. What is a HashMap in Java?
Answer: A HashMap in Java is a data structure that allows you to store and retrieve key-value pairs. It uses a hash function to map keys to their corresponding values, making retrieval very fast.
7. What is the difference between a HashMap and a Hashtable in Java?
Answer: The main difference between a HashMap and a Hashtable in Java is that a HashMap is not synchronized and is not thread-safe, while a Hashtable is synchronized and is thread-safe. Additionally, a HashMap allows null values and keys, while a Hashtable does not.
8. What is a TreeSet in Java?
Answer: A TreeSet in Java is a data structure that represents a set of objects sorted in ascending order according to their natural ordering or a custom Comparator.
9. What is the difference between a HashSet and a TreeSet in Java?
Answer: The main difference between a HashSet and a TreeSet in Java is that a HashSet is an unordered collection of objects that does not allow duplicates, while a TreeSet is a sorted collection of objects that does not allow duplicates.
10 What is the purpose of the Comparable interface in Java?
Answer: The Comparable interface in Java is used to define a natural ordering for a class. By implementing the Comparable interface, you can specify how objects of your class should be compared to each other. This is useful for sorting collections of objects, such as TreeSet or Arrays.sort().
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