- What are the two ways to iterate the elements of a collection?
- Can ArrayList have duplicates?
- Is ArrayList thread safe?
- When should you use a LinkedList instead of an ArrayList?
- Which collection is best for insertion and deletion?
- Where do we use LinkedList and ArrayList?
- What is difference between ArrayList and list?
- What is difference between HashMap and Hashtable?
- What is the difference between ArrayList and LinkedList classes in collection framework in Java?
- What is the difference between ArrayList and vector classes in collection framework?
- What are the differences between ArrayList and LinkedList?
- Does ArrayList maintain order?
- What is the time complexity of ArrayList and linked list?
- What is use of linked list over ArrayList?
- How do you make an ArrayList static?
- Is linked list faster than ArrayList?
- Which collection is faster in Java?
- Is ArrayList linked list?
What are the two ways to iterate the elements of a collection?
There are three common ways to iterate through a Collection in Java using either while(), for() or for-each().
While each technique will produce more or less the same results, the for-each construct is the most elegant and easy to read and write..
Can ArrayList have duplicates?
4) Duplicates: ArrayList allows duplicate elements but HashMap doesn’t allow duplicate keys (It does allow duplicate values). 5) Nulls: ArrayList can have any number of null elements. … In HashMap the elements is being fetched by specifying the corresponding key.
Is ArrayList thread safe?
ArrayList , on the other hand, is unsynchronized, making them, therefore, not thread safe. With that difference in mind, using synchronization will incur a performance hit. So if you don’t need a thread-safe collection, use the ArrayList .
When should you use a LinkedList instead of an ArrayList?
LinkedList is fast for adding and deleting elements, but slow to access a specific element. ArrayList is fast for accessing a specific element but can be slow to add to either end, and especially slow to delete in the middle.
Which collection is best for insertion and deletion?
1) As explained above the insert and remove operations give good performance ( O(1) ) in LinkedList compared to ArrayList( O(n) ). Hence if there is a requirement of frequent addition and deletion in application then LinkedList is a best choice.
Where do we use LinkedList and ArrayList?
ArrayList provides constant time for search operation, so it is better to use ArrayList if searching is more frequent operation than add and remove operation. The LinkedList provides constant time for add and remove operations. So it is better to use LinkedList for manipulation.
What is difference between ArrayList and list?
Well, the main difference between List and ArrayList is that List is an interface while ArrayList is a class. Most importantly, it implements the List interface, which also means that ArrayList is a subtype of List interface.
What is difference between HashMap and Hashtable?
1. HashMap is non synchronized. It is not-thread safe and can’t be shared between many threads without proper synchronization code whereas Hashtable is synchronized. … HashMap allows one null key and multiple null values whereas Hashtable doesn’t allow any null key or value.
What is the difference between ArrayList and LinkedList classes in collection framework in Java?
LinkedList uses Doubly Linked List to store its elements. ArrayList is slow as array manipulation is slower. LinkedList is faster being node based as not much bit shifting required. ArrayList implements only List.
What is the difference between ArrayList and vector classes in collection framework?
Data Growth: ArrayList and Vector both grow and shrink dynamically to maintain optimal use of storage – but the way they resize is different. ArrayList increments 50% of the current array size if the number of elements exceeds its capacity, while vector increments 100% – essentially doubling the current array size.
What are the differences between ArrayList and LinkedList?
ArrayList and LinkedList both implements List interface and maintains insertion order. 1) ArrayList internally uses a dynamic array to store the elements. … LinkedList internally uses a doubly linked list to store the elements.
Does ArrayList maintain order?
ArrayList maintains the insertion order i.e order of the object in which they are inserted. HashSet is an unordered collection and doesn’t maintain any order. ArrayList allows duplicate values in its collection.
What is the time complexity of ArrayList and linked list?
SummaryOperationLinkedList time complexityArrayList time complexitySearch by valueO(N)O(N)Get by indexO(N)O(1)Remove by valueO(N)O(N)Remove by indexO(N)O(N)2 more rows•Aug 16, 2019
What is use of linked list over ArrayList?
When to use LinkedList over ArrayList in Java. LinkedList should be used where modifications to a collection are frequent like addition/deletion operations. LinkedList is much faster as compare to ArrayList in such cases. In case of read-only collections or collections which are rarely modified, ArrayList is suitable.
How do you make an ArrayList static?
This is the older, pre-Java 9 approach I used to use to create a static List in Java (ArrayList, LinkedList): static final List
Is linked list faster than ArrayList?
ArrayList is faster than LinkedList if I randomly access its elements. … ArrayList has direct references to every element in the list, so it can get the n-th element in constant time. LinkedList has to traverse the list from the beginning to get to the n-th element. LinkedList is faster than ArrayList for deletion.
Which collection is faster in Java?
If you need fast access to elements using index, ArrayList should be choice. If you need fast access to elements using a key, use HashMap. If you need fast add and removal of elements, use LinkedList (but it has a very poor seeking performance).
Is ArrayList linked list?
ArrayList is implemented as a resizable array. … It’s elements can be accessed directly by using the get and set methods, since ArrayList is essentially an array. LinkedList is implemented as a double linked list. Its performance on add and remove is better than Arraylist, but worse on get and set methods.