Fredy  Larson

Fredy Larson

1602320136

Go Java (We’re Going to Need a Better JVM)

If you like the go concurrency features of go_routines_ and would like something similar for high-throughput concurrent applications written in Java, then read on …

Summary

To get anything comparable to a goroutine in Java we look at an alternative OpenJDK called Project Loom that provides ‘virtual threads’, a new implementation of Thread that differs in memory footprint and scheduling.

Routines

Java does not have anything that is equivalent to a goroutine, the nearest match is a Thread, unlike Java threads though, you can run many more goroutines on a typical system, they will have a lower memory footprint, and will perform much better.

Java Threads

So whats the problem with Java Threads? In a nutshell, they are implemented in the JDK as trivial wrappers around operating system (OS) threads which introduces the following problems …

OS thread limit

If you try and create too many OS threads you’ll get:

[error] (run-main-0) java.lang.OutOfMemoryError: unable to create native thread

On my macbook (2.2 GHz Intel Core i7, 16 GB 1600 MHz DDR3) I could create 2048 threads before “running out of memory”, this is actually linked to the kern.num_taskthreads setting of 2048, so problem here was not so much to do with memory, but the number of threads the OS supports for my user. All platforms will impost limits though.

#golang #goroutines #java #project-loom #go

What is GEEK

Buddha Community

Go Java (We’re Going to Need a Better JVM)
Tyrique  Littel

Tyrique Littel

1600135200

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

Samanta  Moore

Samanta Moore

1620458875

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

Fredy  Larson

Fredy Larson

1602320136

Go Java (We’re Going to Need a Better JVM)

If you like the go concurrency features of go_routines_ and would like something similar for high-throughput concurrent applications written in Java, then read on …

Summary

To get anything comparable to a goroutine in Java we look at an alternative OpenJDK called Project Loom that provides ‘virtual threads’, a new implementation of Thread that differs in memory footprint and scheduling.

Routines

Java does not have anything that is equivalent to a goroutine, the nearest match is a Thread, unlike Java threads though, you can run many more goroutines on a typical system, they will have a lower memory footprint, and will perform much better.

Java Threads

So whats the problem with Java Threads? In a nutshell, they are implemented in the JDK as trivial wrappers around operating system (OS) threads which introduces the following problems …

OS thread limit

If you try and create too many OS threads you’ll get:

[error] (run-main-0) java.lang.OutOfMemoryError: unable to create native thread

On my macbook (2.2 GHz Intel Core i7, 16 GB 1600 MHz DDR3) I could create 2048 threads before “running out of memory”, this is actually linked to the kern.num_taskthreads setting of 2048, so problem here was not so much to do with memory, but the number of threads the OS supports for my user. All platforms will impost limits though.

#golang #goroutines #java #project-loom #go

Joseph  Murray

Joseph Murray

1623304800

Why We Need Collection Framework in Java?

A framework is a set of classes and interfaces which provide a ready-made architecture. In order to implement a new feature or a class, there is no need to define a framework. However, an optimal object-oriented design always includes a framework with a collection of classes such that all the classes perform the same kind of task. Before Collection Framework(or before JDK 1.2) was introduced, the standard methods for grouping Java objects (or collections) were Arrays or Vectors, or Hash tables. All of these collections had no common interface. Therefore, though the main aim of all the collections is the same, the implementation of all these collections was defined independently and had no correlation among them. And also, it is very difficult for the users to remember all the different methods, syntax, and constructors present in every collection class.

Collection Framework is a powerful framework in java. This framework defines the most common methods that can be used for any collection of objects. But the question arises that we have an array concept in java then why we need collection framework in java? Now let’s see that why we need collection framework in java with some valid points of difference between array and collection.

#java #java-collections #why we need collection framework in java #java collections framework #framework in java

Samanta  Moore

Samanta Moore

1620462686

Spring Boot and Java 16 Records

In this article, we will discuss Java 16’s newest feature, Records. Then we will apply this knowledge and use it in conjunction with a Spring Boot application.

On March 16th, 2021, Java 16 was GA. With this new release, tons of new exciting features have been added. Check out the release notes to know more about these changes in detail. This article’s focus will be on Java Records, which got delivered with JEP 395. Records were first introduced in JDK 14 as a preview feature proposed by JEP 359, and with JDK 15, they remained in preview with JEP 384. However, with JDK 16, Records are no longer in preview.

I have picked Records because they are definitely the most favored feature added in Java 16, according to this Twitter poll by Java Champion Mala Gupta.

I also conducted a similar survey, but it was focused on features from Java 8 onwards. The results were not unexpected, as Java 8 is still widely used. Very unfortunate, though, as tons of new features and improvements are added to newer Java versions. But in terms of features, Java 8 was definitely a game-changer from a developer perspective.

So let’s discuss what the fuss is about Java Records.

#java #springboot #java programming #records #java tutorials #java programmer #java records #java 16