Both Vector and ArrayList implement the List interface, and each of them uses (dynamically resizable) arrays for their internal data structure, similar to using an ordinary array. However, there are many differences between ArrayList and Vector classes hence by reading this article, you will learn what ArrayList and Vector class are and their major difference that helps you to choose which one to opt for. Understanding ArrayList and Vector Class In addition to the Arrays class, Java provides an ArrayList class that can be used to create containers that stores lists of objects. ArrayList is considered to be a growable ... Read More

The ensureCapacity(int minCapacity) method of the class java.util.ArrayList increases the capacity of this ArrayList instance, if necessary, to ensure that it can hold at least the number of elements specified by the minimum capacity argument.Exampleimport java.util.ArrayList; public class ArrayListDemo {    public static void main(String args[]) {       ArrayList arrlist = new ArrayList(5);       arrlist.add(10);       arrlist.add(50);       arrlist.add(30);       arrlist.ensureCapacity(15);       for (Integer number : arrlist) {          System.out.println("Number = " + number);       }    } }OutputNumber = 10 Number = 50 Number = 30

The lastIndexOf(Object) method of the class java.util.ArrayList returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.Exampleimport java.util.ArrayList; public class ArrayListDemo {    public static void main(String[] args) {       ArrayList arrlist = new ArrayList(5);       arrlist.add("G");       arrlist.add("E");       arrlist.add("F");       arrlist.add("M");       arrlist.add("E");       System.out.println("Size of list: " + arrlist.size());       for (String value : arrlist) {          System.out.println("Value = " + value);     ... Read More

ArrayList doesn't have length() method, the size() method of ArrayList provides the number of objects available in the collection.Array has length property which provides the length or capacity of the Array. It is the total space allocated during the initialization of the array.

The addAll(Collection

The indexOf(Object) method of the java.util.ArrayList class returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.Exampleimport java.util.ArrayList; public class ArrayListDemo {    public static void main(String[] args) {       ArrayList arrlist = new ArrayList(5);       arrlist.add("G");       arrlist.add("E");       arrlist.add("F");       arrlist.add("M");       System.out.println("Size of list: " + arrlist.size());       for (String value : arrlist) {          System.out.println("Value = " + value);       }     ... Read More

The search(Object o) method is used to return the 1-based position where an object is on this stack.Exampleimport java.util.*; public class StackDemo {    public static void main(String args[])  {             Stack st = new Stack();       st.push("Java");       st.push("Source");       st.push("code");       System.out.println("Searching 'code' in stack: "+st.search("code"));    } }OutputSearching 'code' in stack: 

The get(int index) method of the java.util.ArrayList class returns the element at the specified position in this list.Exampleimport java.util.ArrayList; public class ArrayListDemo {    public static void main(String[] args) {       ArrayList arrlist = new ArrayList(5);       arrlist.add(15);       arrlist.add(22);       arrlist.add(30);       arrlist.add(40);       for (Integer number : arrlist) {          System.out.println("Number = " + number);       }       int retval=arrlist.get(3);       System.out.println("Retrieved element is = " + retval);    } }OutputNumber = 15 Number = 22 Number = 30 Number = 40 Retrieved element is = 40

The empty() method is used to test if this stack is or not.Exampleimport java.util.*; public class StackDemo {    public static void main(String args[]) {           Stack st = new Stack();       st.push("Java");       st.push("Source");       st.push("code");       System.out.println("Is stack empty: "+st.empty());    } }OutputIs stack empty: false

The peek() method is used to look at the object at the top of this stack without removing it from the stack.Exampleimport java.util.*; public class StackDemo {    public static void main(String args[]) {             Stack st = new Stack();       st.push("Java");       st.push("Source");       st.push("code");       System.out.println("Top object is: "+st.peek());    } }OutputTop object is: code