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Object Oriented Programming Articles
Page 338 of 589
Java program to find Largest, Smallest, Second Largest, Second Smallest in an array
In this problem we are given an array of numbers, and we have to find the largest, smallest, second largest, and second smallest elements in an array in Java. Let’s understand the problem better with the help of an example: Input int arr[] = {55, 10, 8, 90, 43, 87, 95, 25, 50, 12}; Output Smallest element = 8 2nd Smallest element = 10 Largest element = 95 2nd Largest element = 90 To solve this problem, use the following approaches: Using Arrays.sort() Using nested for-loops Optimized one-pass approach Using Arrays.sort() In this ...
Read MoreFind average of a list in Java
Given a list of numbers, our task is to calculate the average of this list. The average of a list can be found by adding all the elements in the list and dividing the sum by the total number of elements. In this article we will learn different methods to implement this in Java. There are multiple ways in Java to find the average of a list. In this article we will explore two different approaches: Using Java Streams Using for loop Find Average of a List Using Java Streams This approach shows how to find ...
Read MoreDifference between Scanner and BufferReader Class in Java
Scanner and BufferedReader classes are used to read input from an external system. Scanner is normally used when we know input is of type string or of primitive types, and BufferedReader is used to read text from character streams while buffering the characters for efficient reading of characters. What is Scanner Class? The Scanner class is included in the java.util package. It is mostly used when the data type of the input is already known. We commonly use it with data ty+pes like strings, integers, floats, and booleans. It has built-in methods like nextInt(), nextDouble(), and nextLine() that help ...
Read MoreDifferences between abstract class and concrete class in Java
Abstract class and concrete class are fundamental concepts of object oriented programming in Java. In this article, we will learn the differences between an abstract class and concrete class. What is an Abstract Class? An abstract class is a class that cannot be used to create objects. It can only be accessed using its subclasses. It can contain abstract methods, which are methods without a body. It acts as a blueprint for its subclasses. It can also contain concrete or regular methods. Example This example shows how to implement an abstract class in java: ...
Read MoreWhat are the differences between paint() method and repaint() method in Java?
In this article, we will learn about the differences between the paint() method and the repaint() method in Java. In the AWT and Swing frameworks, rendering graphical components is done in two different roles by the two methods paint() and repaint(). The paint() Method This method holds instructions to paint this component. In Java Swing, we can change the paintComponent() method instead of paint() method as paint calls paintBorder(), paintComponent() and paintChildren() methods. We cannot call this method directly instead we can call repaint(). Syntax The following is the syntax: public void paint(Graphics g) { // paint() method ...
Read MoreHow can we minimize/maximize a JFrame programmatically in Java?
In this article, we will learn to minimize/maximize a JFrame programmatically in Java. In Swing, programmers often need to resize the window as needed. For example, they can shrink the window when carrying out background tasks or expand the window size for a better full-screen experience. What is a JFrame? A JFrame class is a subclass of Frame class and the components added to a frame are referred to as its contents, these are managed by the contentPane. A JFrame contains a window with title, border, (optional) menu bar and user-specific components. By default, we can minimize a JFrame by ...
Read MoreDifference between Stack and Heap memory in Java
JVM has divided memory space between two parts: one is Stack and another one is Heap space. Stack space is mainly used for storing order of method execution and local variables. Stacks always store blocks in LIFO order whereas heap memory uses dynamic allocation for allocating and deallocating memory blocks. Memory allocated to the heap lives until one of the following events occurs : Program terminated Memory free What is a Heap memory? Heap memory is allocated for storing objects, arrays, and JRE (Java Runtime Environment) classes. Memory may be ...
Read MoreDifference Between ReentrantLock and Synchronized in Java
There are two ways to get a lock on the shared resource by multiple threads. One is a Reentrant Lock (or read/write lock), and the other is by using the Synchronized method. The reentrant lock class has been provided in the Java concurrency package from Java 5. It is the implementation of the Lock interface, and according to Java docs, the implementation of the Lock interface provides more extensive operation than can be obtained using synchronized method. What is the Reentrant lock? ReetrantLock is a class that implements the Lock Interface. It provides the synchronization feature with great flexibility, ...
Read MoreDifference between Serialization and Externalization in Java
Serialization and externalization both are the processes of converting an object to stream byte and storing byte stream in database or memory. The class that implements java.io.Serializable interface can be serialized. What is Serialization? Java provides a mechanism called object serialization where an object can be converted into a byte stream that includes the object's data and details about the object's type. Example The following is an example of Serialization in Java: import java.io.Serializable; class SerializableExample implements Serializable { private static final long serialVersionUID = 5081877L; String name; } public ...
Read MoreDifference between Concurrent hash map and Synchronized hashmap in Java
A Map is an object that stores key-value pairs, where each key is unique but values can repeat. The HashMap is a type of Map that uses a hashtable in order to store these pairs. Now we will discuss the differences between ConcurrentHashMap and Synchronized Hashmap. What is a ConcurrentHashMap? ConcurrentHashMap is a class that was introduced in jdk1.5. ConcurrentHashMap applies locks only at bucket level called fragment while adding or updating the map. So, aConcurrentHashMap allows concurrent read and write operation to the map. Example of ConcurrentHashMap The following is an example of ConcurrentHashMap in java − import java.util.Map; ...
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