Found 9150 Articles for Object Oriented Programming

What is a method signature in Java?

Swarali Sree
Updated on 30-Jul-2019 22:30:20

7K+ Views

The method signature consists of the method name and the parameter list. Example Live Demo public class MethodSignature { public int add(int a, int b){ int c = a+b; return c; } public static void main(String args[]){ MethodSignature obj = new MethodSignature(); int result = obj.add(56, 34); System.out.println(result); } } Output 90 Method ... Read More

How to create and write JSON array to a file in java?

Abhinaya
Updated on 19-Feb-2020 12:26:38

4K+ Views

Java provides javax.json.Json package which contains classes to read a JSON array:Exampleimport java.io.FileOutputStream; import javax.json.Json; import javax.json.JsonArray; import javax.json.JsonWriter; public class JSONArrayToFile {    public static void main(String args[]) throws Exception {       JsonArray value = Json.createArrayBuilder()          .add(Json.createObjectBuilder()          .add("id", "1001")          .add("Technology", "JavaFX"))          .add(Json.createObjectBuilder()          .add("id", "1002")          .add("Technology", "OpenCV"))          .build();       System.out.println(value);       JsonWriter writer = Json.createWriter(new FileOutputStream("sampleData"));       writer.writeArray(value);       writer.close();    } }Output["JavaFX","HBase","JOGL","WebGL"] After deleting ::["JavaFX","HBase","JOGL"]

What is the super class of every class in Java?

Alshifa Hasnain
Updated on 28-Feb-2025 18:48:15

6K+ Views

The Object class is the superclass of every single class in Java. This position implies that every class in Java, even if a built-in class or function like String or a user-defined one, directly or indirectly inherits from Object. Understanding the Object Class The Object class provides fundamental methods that every Java object inherits. Even if a class does not explicitly extend another class, it implicitly extends Object. Below is a demostration of the same − class Example { //This class implicitly extends to an Object } Why Does Every Class Inherit from ... Read More

How to remove a specific element from a JSON Array in Java?

Govinda Sai
Updated on 19-Feb-2020 12:25:46

15K+ Views

You can remove an element from the JSONArray object using the remove() method. This method accepts an integer and removes the element in that particular index.Exampleimport org.json.JSONArray; public class RemoveFromJsonArray {    public static void main(String args[]) throws Exception {       String [] myArray = {"JavaFX", "HBase", "JOGL", "WebGL"};       JSONArray jsArray = new JSONArray();       for (int i=0; i < myArray.length; i++) {          jsArray.put(myArray[i]);      }      System.out.println(jsArray);      jsArray.remove(3);      System.out.println("After deleting ::"+jsArray);    } }Output["JavaFX","HBase","JOGL","WebGL"] After deleting ::["JavaFX","HBase","JOGL"]

Can a final class be subclassed in Java?

Alshifa Hasnain
Updated on 27-Feb-2025 19:28:35

2K+ Views

In Java Inheritance is a fundamental feature that allows a class to derive properties and behaviors from another class. In Java, not all classes can be subclassed. A final class is a special type of class that cannot be extended.  What is a Final Class in Java? In Java, a class is declared final using the final keyword. The final modifier for finalizing the implementations of classes, methods, and variables. When a class is marked as final, it means − It cannot be extended. All its methods remain unchanged in their ... Read More

How to convert JSON Array to normal Java Array?

Ramu Prasad
Updated on 19-Feb-2020 12:24:47

3K+ Views

The get method of the JSONArray class returns the element at a particular index. Using this method, you can get the elements of the JSONArray object and populate the array with them.Exampleimport java.util.Arrays; import org.json.JSONArray; public class JsonToArray {    public static void main(String args[]) throws Exception {       String [] myArray = {"JavaFX", "HBase", "JOGL", "WebGL"};       JSONArray jsArray = new JSONArray();       for (int i = 0; i < myArray.length; i++) {          jsArray.put(myArray[i]);      }      System.out.println(jsArray);      String[] array = new String[myArray.length];   ... Read More

How to convert Java Array/Collection to JSON array?

Sravani S
Updated on 30-Jul-2019 22:30:20

8K+ Views

Google provides a library named org.json.JSONArray and, following is the maven dependency to add library to your project. com.googlecode.json-simple json-simple 1.1 The JSONArray class of the org.json package provides put() method. Using this method, you can populate the JSONArray object with the contents of the elements.Exampleimport org.json.JSONArray; public class ArrayToJson { public static void main(String args[]) { String [] myArray = {"JavaFX", "HBase", "JOGL", "WebGL"}; JSONArray jsArray = new JSONArray(); ... Read More

How to perform binary search on an array in java?

V Jyothi
Updated on 16-Jun-2020 10:17:11

199 Views

The Arrays class of java package provides you a method named binarySearch() using this method you can perform a binary search on an array in Java.ExampleLive Demoimport java.util.Arrays; public class ArrayDemo {    public static void main(String[] args) {       int intArr[] = {30,20,5,12,55};       Arrays.sort(intArr);       System.out.println("The sorted int array is:");       for (int number : intArr) {          System.out.println("Number = " + number);       }       int searchVal = 12;       int retVal = Arrays.binarySearch(intArr,searchVal);       System.out.println("The index of element 12 is : " + retVal);    } }OutputThe sorted int array is: Number = 5 Number = 12 Number = 20 Number = 30 Number = 55 The index of element 12 is: 1

How to perform heapsort on an array in Java?

Priya Pallavi
Updated on 19-Feb-2020 12:22:49

679 Views

Following is the algorithm for heapsort (maxheap).Step 1 − Create a new node at the end of the heap.Step 2 − Assign new value to the node.Step 3 − Compare the value of this child node with its parent.Step 4 − If the value of parent is less than a child, then swap them.Step 5 − Repeat step 3 & 4 until Heap property holds.Exampleimport java.util.Arrays; import java.util.Scanner; public class Heapsort {    public static void heapSort(int[] myArray, int length) {       int temp;       int size = length-1;       for (int i ... Read More

How to check if array contains three consecutive dates in java?

Nikitha N
Updated on 19-Feb-2020 12:22:03

1K+ Views

To check to find whether a given array contains three consecutive dates:Convert the given array into a list of type LocalDate.Using the methods of the LocalDate class compare ith, i+1th and i+1th, i+2th elements of the list if equal the list contain 3 consecutive elements.ExampleLive Demoimport java.time.LocalDate; import java.time.Month; import java.util.ArrayList; import java.util.Collections; import java.util.Date; import java.util.List; public class ConsicutiveDate {    public static void main(String args[]) {       String[] dates = {"5/12/2017", "6/12/2017", "7/12/2017"};       List localDateList = new ArrayList();       for (int i = 0; i

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