Posted inJava Java Advanced
How to Build a Web Scraper in Java
Hello, Today we are going to build a web scraper. Although All of you know the term, I just want to tell you shortly what exactly web scraper is? Web…
[solved] caused by: org.hibernate.PersistentObjectException: detached entity passed to persist:
The error looks like org.hibernate.PersistentObjectException: detached entity passed to persist: example.forms.InvoiceItem at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:127) at org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:799) at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:791) …
Posted inJava
How to create Spring Boot Application 2021
Hi Devs, Today I am going to show you how to create a simple spring boot project from scratch. Go to spring initializer to generate a spring boot project. Spring…
Posted inInterview Questions Java Java Basic
Convert array to ArrayList java
In this article, we are converting an array to ArrayList in Java. We will discuss three different ways to do that. So, I will show how to convert an Array…
Posted inInterview Questions Java Java Advanced
Java pass by reference
Is java pass by reference? The answer is NO. Java is always pass-by-value. Today we will learn java pass by reference and java pass by value with examples. Let’s create Person class: package com.example; public…
Posted inJava Advanced Java
Java null pointer exception
Today we will learn, What is a NullPointerException, and how do I fix it? So, let’s start: What is NullPointException NullPointException is a RunTimeException. NullPointException is thrown when the value…
Posted inJava Java Basic
Operators in Java Explained
Operator are those who performs an action, for example + is an arithmetic operator that perform addition. They are various types of operators are available in java programming language. Types of…
Posted inJava Java Basic
Data Types in Java Explained
In Java, data types refer to the type of data that can be stored in variables. Because Java is a tightly typed language, you must define the datatype of variables…
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Variables in Java Explained
A variable is a term that refers to a value that can be changed in the future. When I put int i=10, for example, the variable name is I and the value…
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Java Hello World Program
We’ll learn how to write our first Java program throughout this post. This article is only for java beginners. hello world program will be a very simple program that will…
Posted inJava Java Basic
Difference between JDK vs JRE vs JVM
Table of contents What is JDKFeatures of JDKWhat is JREFeatures of JREWhat is JVMMain Task of JVMFeatures of JVM What is JDK JDK is the acronym of JAVA Development Kit. JDK…
Posted inJava Java Basic
Introduction to Java Programming Language
Java is one of the most used programming languages in the world for developing desktop application and web application. What is JAVA? Java is a platform independent, object oriented programming…
Posted inJava Advanced Uncategorized
What is a serialVersionUID and why should I use it?
Serialization Serialization allows to convert an object to a stream, for sending that object over the network OR Save to file OR save into DB for letter usage. serialVersionUID It is…
A JNI error has occurred, please check your installation and try again problem fix 2021
Hi, This is a common problem when you want to run a java program using the command line. The problem is occurring for so many reasons. Most of the cause…
Posted inJava Java Advanced
How to handle null pointer exception in Java
NullPointException NullPointException is a RunTimeException. NullPointException is thrown when the value of a reference variable or object is null. How to avoid NullPointException? Before using any object or reference variable,…
Posted inJava Java Advanced
How to handle IOException in Java
IOException In Java, IOException is one of the most common Exceptions when the program operates between input and output.IOException is used for input and output-related operations. Sometimes it’s called Input-Output Exception. Whatever the reason…
Posted inJava Java Advanced
Exception handling in java with examples
Exception Handling in Java is a powerful mechanism. Exception handling is done to handle the run time error of the program and to maintain normal flow. The exception refers to an abnormal…
Java Encapsulation
Binding (or wrapping) code and data together into a single unit are known as encapsulation. For example, a capsule is wrapped with different medicines. Java Encapsulation reduces the code redundancy…
Java Abstraction
Hiding internal details and showing functionality is known as abstraction. For example phone call, we don't know the internal processing. The user will have the information on what the object…
Java Polymorphism
If one task is performed in different ways, it is known as polymorphism. For example: to convince the customer differently, to draw something, for example, shape, triangle, rectangle, etc. In…