Synchronization - ArrayList is not thread-safe whereas Vector is thread-safe. In Vector class each method like add() , get(int i) is surrounded with a synchronized block, thus making Vector class thread-safe. Data growth - Internally, both the ArrayList and Vector hold onto their contents using an Array. When an element is inserted into an ArrayLis...

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ArrayList can be synchronized using below step: Collections.synchronizedList(List list)

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Arrays are created of fix size whereas ArrayList is dynamic in nature and can vary its length. Also the size of array cannot be incremented or decremented, but with ArrayList the size is variable. Once the Array is created elements cannot be added or deleted from it. But with ArrayList the elements can be added and deleted at run time. List list = ...

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An ArrayList is implemeted by its namesake i.e Array. The first question that should arise is how is a fixed size data structure providing an implementation for a dynamically growing one. The answer is simple, the data is copied to a new and larger sized array and the older one is discarded (Garbage collector , please note). This makes addition of ...

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While both are a type of Collection, List and Set are inherently very different from each other. Salient differences are List Set List is an ordered collection it maintains the insertion order, which means upon displaying the list content it will display the elements in the same order in which they got inserted into the list. Set is an un-ordered c...

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ArrayList is like a grow able array. It permits all list operations, accepts duplicate elements including null. Adding an element in an ArrayList has constant amortized cost i.e adding n elements requires O (n) time. The ArrayList class extends AbstractList and implements the List interface. ArrayList supports dynamic arrays that can grow as needed...

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ArrayList is resizable and implementation of the  List interface that is backed by an array. It permits addition of duplicate elements including null. The class provides its own implementation to dynamically manipulate the size of the array that it uses internally to store the elements. So, as we all know that Array is a fixed size data structure, ...

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Iterator and ListIterator of ArrayList in Java are Fail – Fast in nature. What that means is, if an ArrayList is modified at any time after the iterator is created in any way other than iterator’s own methods, the iterator will throw a ConcurrentModificationException.   Let’s see an example: import java.util.ArrayList; import java.util.Iterator;...

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LinkedList is doubly-linked list implementation of the List and Deque interfaces. Implements all optional list operations, and permits all elements (including null). All of the operations perform as could be expected for a doubly-linked list. Operations that index into the list will traverse the list from the beginning or the end, whichever is clos...

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LinkedList provides two constructors: LinkedList() – Constructs an empty list. LinkedList(Collection c) – Constructs a list containing the elements of the specified collection, in the order they are returned by the collection’s iterator. If we check the code for this constructor : public LinkedList(Collection c) {     // first callin...

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Commonly used methods are more or less the same like that of ArrayList. The newer methods that we should turn our attention to are:     void addFirst(E e) Inserts the specified element at the beginning of this list.     void addLast(E e) Appends the specified element to the end of this list.     E getFirst() – Returns the first element in this list...

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Here we can see example for basic operations like creating object for LinkedList, adding objects into LinkedList, searching an object in LinkedList, whether it is listed under this LinkedList instance or not, checking whether the LinkedList is empty or not, and finally size of the LinkedList. package com.tuturself.web.test; import java.util.LinkedL...

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Here we can see example for reading all elements from Linked List by using Iterators. First we will iterate over the Linked List using Iterator. Then we will use a List Iterator to iterate over the linked List. Once done the we will use the same List Iterator to iterate over the linked list in backward direction. (Reverse direction) package com.tut...

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List is an ordered collection which means it maintains the order of the elements you have inserted and it is also known as a sequence. So you will have complete control on where in the list each element is inserted. You can access elements by their integer index (position in the list), and also search for elements in it. Lists (like Java arrays) ar...

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boolean remove(Object o): Removes the first occurrence and a single instance of the specified element from the list, if it is present. More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if this collection contains one or more such elements. It returns true if this collection contained the specified element (or if this ...

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ArrayList implements the List Interface. If you look at the Javadoc for List at the contains method you will see that it uses the equals() method to evaluate if two objects are the same.The method signature in the Java interface List is : boolean contains(Object o). As per the Java documentation, it returns true if and only if this list contains ...

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A lot of people get confused on this question and answer that since Lists allow duplicates, we do not need to override the equals() and hashcode() methods. That is not incorrect but neither is that the correct answer. Let's consider some of the methods provided by the List interface. boolean contains(Object o); boolean remove(Object o); boolean...

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Here in this post we will discuss about finding an Custom Object in an ArrayList. The List interface has a contains method , which we can use to find an Object in a List. boolean contains(Object o) Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such th...

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There are two ways to synchronize an ArrayList: Using Collections.synchronizedList() method. Using thread-safe variant of ArrayList : CopyOnWriteArrayList Example 1 : In this example we are using Collections.synchronizedList() method. The important point to note here is that iterator should be in synchronized block in this type of synchronization a...

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