Create a Read-Only Collection in Java

Arushi
Updated on 30-Jun-2020 08:28:36

221 Views

An example of a read-only collection can be an unmodifiable ArrayList. The unmodifiable view of the specified ArrayList can be obtained by using the method java.util.Collections.unmodifiableList(). This method has a single parameter i.e. the ArrayList and it returns the unmodifiable view of that ArrayList.A program that demonstrates this is given as follows −Example Live Demoimport java.util.ArrayList; import java.util.Collections; import java.util.List; public class Demo {    public static void main(String args[]) throws Exception {       List aList = new ArrayList();       aList.add("Apple");       aList.add("Mango");       aList.add("Guava");       aList.add("Orange");       aList.add("Peach"); ... Read More

Enumerate Through Vector Elements in Java

Rishi Raj
Updated on 30-Jun-2020 08:25:07

753 Views

The Vector elements can be traversed using the Enumeration interface. The method hasMoreElements( ) returns true if there are more elements to be enumerated and false if there are no more elements to be enumerated. The method nextElement( ) returns the next object in the enumeration.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Enumeration; import java.util.Vector; public class Demo {    public static void main(String args[]) {       Vector vec = new Vector();       vec.add(7);       vec.add(3);       vec.add(5);       vec.add(9);       vec.add(2);     ... Read More

Loop Through Vector Elements Using an Iterator in Java

Jai Janardhan
Updated on 30-Jun-2020 08:22:40

2K+ Views

An Iterator can be used to loop through the Vector elements. The method hasNext( ) returns true if there are more elements in the Vector and false otherwise. The method next( ) returns the next element in the Vector and throws the exception NoSuchElementException if there is no next element.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Iterator; import java.util.Vector; public class Demo {    public static void main(String args[]) {       Vector vec = new Vector();       vec.add(4);       vec.add(1);       vec.add(3);       vec.add(9);     ... Read More

Loop Through Vector Elements Using ListIterator in Java

Arushi
Updated on 30-Jun-2020 08:21:33

207 Views

A ListIterator can be used to traverse the elements in the forward direction as well as the reverse direction in a Vector. The method hasNext( ) in ListIterator returns true if there are more elements in the Vector while traversing in the forward direction and false otherwise. The method next( ) returns the next element in the Vector and advances the cursor position.A program that demonstrates this is given as follows −Exampleimport java.util.ListIterator; import java.util.Vector; public class Demo {    public static void main(String args[]) {       Vector vec = new Vector();       vec.add(3);     ... Read More

Find the Maximum Element of a Vector in Java

Arushi
Updated on 30-Jun-2020 08:20:22

1K+ Views

The maximum element of a Vector can be obtained using the java.util.Collections.max() method. This method contains a single parameter i.e. the Vector whose maximum element is determined and it returns the maximum element from the Vector.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Collections; import java.util.Vector; public class Demo {    public static void main(String args[]) {       Vector vec = new Vector();       vec.add(7);       vec.add(3);       vec.add(9);       vec.add(5);       vec.add(8);       System.out.println("The Vector elements are: " + vec);     ... Read More

Find Minimum Element of a Vector in Java

Jai Janardhan
Updated on 30-Jun-2020 08:19:28

552 Views

The minimum element of a Vector can be obtained using the java.util.Collections.min() method. This method contains a single parameter i.e. the Vector whose minimum element is determined and it returns the minimum element from the Vector.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Collections; import java.util.Vector; public class Demo {    public static void main(String args[]) {       Vector vec = new Vector();       vec.add(7);       vec.add(3);       vec.add(9);       vec.add(5);       vec.add(8);       System.out.println("The Vector elements are: " + vec);     ... Read More

Convert a Vector to an Array in Java

Vikyath Ram
Updated on 30-Jun-2020 08:18:22

1K+ Views

A Vector can be converted into an Array using the java.util.Vector.toArray() method. This method requires no parameters and it returns an Array that contains all the elements of the Vector in the correct order.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Vector; public class Demo {    public static void main(String args[]) {       Vector vec = new Vector();       vec.add(7);       vec.add(3);       vec.add(5);       vec.add(2);       vec.add(8);       Object[] arr = vec.toArray();       System.out.println("The Array elements are: ");   ... Read More

Clone a Vector in Java

Rishi Raj
Updated on 30-Jun-2020 08:16:58

324 Views

A Vector can be cloned using the java.util.Vector.clone() method. This method does not take any parameters but returns a clone of the specified Vector instance as an object.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Vector; public class Demo {    public static void main(String args[]) {       Vector vec1 = new Vector();       vec1.add(7);       vec1.add(3);       vec1.add(5);       vec1.add(9);       vec1.add(2);       Vector vec2 = (Vector) vec1.clone();       System.out.println("The Vector vec1 elements are: " + vec1);       ... Read More

Get Reverse Order Using Comparator in Java

Vikyath Ram
Updated on 30-Jun-2020 08:16:08

862 Views

The objects of a user defined class can be ordered using the Comparator interface in Java. The java.util.Collections.reverseOrder() method reverses the order of an element collection using a Comparator.A program that demonstrates this is given as follows −Exampleimport java.util.Arrays; import java.util.Collections; import java.util.Comparator; public class Demo {    public static void main(String args[]) throws Exception {       Comparator comparator = Collections.reverseOrder(); { "John", "Amy", "Susan", "Peter" };       int n = str.length;       System.out.println("The array elements are: ");       for (int i = 0; i < n; i++) {       ... Read More

Filter Specific Values from a MongoDB Document

AmitDiwan
Updated on 30-Jun-2020 08:15:02

594 Views

To filter specific values, use $filter in MongoDB. Let us create a collection with documents −> db.demo751.insertOne( ...    { ...       _id: 101, ...       details: [ ...          { Name: "Robert", id:110, Age:21}, ...          { Name: "Rae", id:110, Age:22}, ...          {Name: "Ralph", id:116, Age:23} ...       ] ...    } ... ); { "acknowledged" : true, "insertedId" : 101 }Display all documents from a collection with the help of find() method −> db.demo751.find().pretty();This will produce the following output −{    "_id" ... Read More

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