Classes in Java

Classes in Java | Java Tutorial for Beginners | Java Classes

A class is a user-defined blueprint or prototype from which objects are created.  It represents the set of properties or methods that are common to all objects of one type. A class can be defined as a template/blueprint that describes the behavior/state that the object of its type support.

1:42 -  Agenda
3:24 -  Introduction to class
6:20 -  Requirement of a class
11:42 -  Elements of a class
13:52 -  Defining a class
16:20 -  Memory allocation
18:51 - Coding standards for classes
22:09  - Access modifiers used for class
27:29 - Encapsulation
29:27 - Question
42:18 - Inner class
59:26 - Summary

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How to Install OpenJDK 11 on CentOS 8

What is OpenJDK?

OpenJDk or Open Java Development Kit is a free, open-source framework of the Java Platform, Standard Edition (or Java SE). It contains the virtual machine, the Java Class Library, and the Java compiler. The difference between the Oracle OpenJDK and Oracle JDK is that OpenJDK is a source code reference point for the open-source model. Simultaneously, the Oracle JDK is a continuation or advanced model of the OpenJDK, which is not open source and requires a license to use.

In this article, we will be installing OpenJDK on Centos 8.

#tutorials #alternatives #centos #centos 8 #configuration #dnf #frameworks #java #java development kit #java ee #java environment variables #java framework #java jdk #java jre #java platform #java sdk #java se #jdk #jre #open java development kit #open source #openjdk #openjdk 11 #openjdk 8 #openjdk runtime environment

Going Beyond Java 8: Local Variable Type Inference (var) - DZone Java

According to some surveys, such as JetBrains’s great survey, Java 8 is currently the most used version of Java, despite being a 2014 release.

What you are reading is one in a series of articles titled ‘Going beyond Java 8,’ inspired by the contents of my book, Java for Aliens. These articles will guide you step-by-step through the most important features introduced to the language, starting from version 9. The aim is to make you aware of how important it is to move forward from Java 8, explaining the enormous advantages that the latest versions of the language offer.

In this article, we will talk about the most important new feature introduced with Java 10. Officially called local variable type inference, this feature is better known as the **introduction of the word **var. Despite the complicated name, it is actually quite a simple feature to use. However, some observations need to be made before we can see the impact that the introduction of the word var has on other pre-existing characteristics.

#java #java 11 #java 10 #java 12 #var #java 14 #java 13 #java 15 #verbosity

Creating an Immutable Class in Java

In this article, we’ll define the typical steps for creating an immutable class in Java and then implement it.

Steps to create Immutable class in java

1. Make your class final, so that no other classes can extend it.
2. Make all fields private so that direct access is not allowed.
3. Don’t provide “setter” methods — methods that modify fields or objects referred to by fields.
4. Special attention when having mutable instance variables
5. Inside the constructor, make sure to use a clone copy of the passed argument and never set your mutable field to the real instance passed through the constructor.
6. Make sure to always return a clone copy of the field and never return the real object instance.

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Top 10 Java Classes from Utility Package

Java.util package contains the collection’s framework, legacy collection classes, event model, date and time facilities, internationalization, and miscellaneous utility classes (a string tokenizer, a random-number generator, and a bit array). Here is the list of most commonly used top ten Java utility classes:

1. Java Arrays Class

Java.util package provides an Arrays class that contains a static factory that allows arrays to be viewed as lists. The class contains various methods for manipulating arrays like sorting and searching. The methods in this class throw a NullPointerException, if the specified array reference is null.

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How to Find All the Classes of a Package in Java

In this article let’s take a look at how to find all classes of a package in Java

To find all classes of a package in Java we can use the ClassHunter of Burningwave Core library. So we start by adding the following dependency to our pom.xml:

XML

1

<dependency>2
    <groupId>org.burningwave</groupId>3
    <artifactId>core</artifactId>4
    <version>8.4.0</version>5
</dependency>

The next steps are the following:

• retrieving the ClassHunter through the ComponentContainer
• defining a regular expression that we must pass to the **ClassCriteria **object that will be injected into the **SearchConfig **object
• calling the **loadInCache **method that loads in the cache all loadable classes of the indicated paths, then applies the criteria filter and then returns the **SearchResult **object which contains the classes that match the criteria

#java #classes #class #packages #package #how to find all the classes of a package in java