## An icon with a counter in the upper toolbar: an example of the diversity of approaches to one task

In the life of each developer there is a time when, seeing an interesting solution in someone else's application, I want to implement it in my own. This is logical and should be quite simple. And for sure, caring people from the "corporation of good" wrote some guide on this or made a training video, where on the fingers it is shown how to call a couple of necessary methods to achieve the desired result. Often happens just so.

But it also happens quite differently: you see the realization of something in every second application, and when it comes to realizing the same in yourself it turns out that ...
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## My favorite examples of functional programming in the language Kotlin

One of the great features of Kotlin is that it supports functional programming. Let's look at and discuss some simple but expressive functions written in Kotlin.

Superset (Boolean)

If you studied algebra at a university, you can recall what a superset is. For any set, its superset is the set of all its subsets, including the original set itself and the empty set. For example, if we have the following set:

{??3}

Then his superset:

{{}, {1}, {2}, {3}, {?2}, {?3}, {?3}, {??3}}

In algebra such a function is very useful. How do we implement it?

If you want to challenge yourself, stop reading ...
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## How to prevent memory overuse while using Java collections

Hello!

Our experiment with the steps at the rate of "The Java Developer" continues, and, oddly enough, even quite successfully (like): as it turned out, the planning shoulder in a couple of months with the next transition to a new stage at any convenient time is much more convenient than if to allocate almost half a year for such a difficult course. So there is a suspicion that it is complex courses that we will soon begin to gradually translate into such a system.

But this I am talking about our, about Ostusovsky, sorry. As always, we continue to study interesting topics that, although ...
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## [Перевод]How Graal works is JV-JIT compiler on Java

Hello, Habr! I present to your attention the translation of the article " : Understanding How Graal Works - a Java JIT Compiler Written in Java ".

Introduction

One of the reasons I became a researcher of programming languages ​​is that, in a large community of people connected with computer technologies, almost everyone uses programming languages, and many are interested in how they work. When I first encountered programming as a child and got acquainted with the programming language, the first thing I wanted to know about was how it works, and the very first thing I wanted to do was create ...
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## Explanation of lambda expressions

I have questions about lambda expressions and RxJava. These questions mainly concern not a complete understanding of lambda expressions or RxJava. I will try to explain lambda expressions as simply as possible. RxJava I will describe separately.

Lambda expressions and RxJava

What are lambda expressions? Lambda expressions are "just" a new way of doing the same thing that we could always do, but in a purer and less verbose new way of using anonymous inner classes.

An anonymous inner class in Java is a class with no name, it should be used if you need to override class or interface methods. An anonymous ...
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## A real contribution to the real Open Source

The recent post is about how we are at Sberbank-Technologies developing Open Source has revealed many interesting details about approaches, aspirations and ideology.

Today I want to talk about the real contribution that our team makes to Open Source.

Apache Ignite and lately we have done a lot of useful things.

So, further only the facts.

1) In version 2.5 a new version of topology appeared: star around the ZooKeeper .

We participated in stabilizing the new functionality and decided ...
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## 9 paid, shareware and free programs for tracking application code

The tracking code must-have in the development environment. But how much do you need the same tool in the product? The one who only painstakingly collects the logs will say "well its nafig, my ELK does not let me down" and will be right in his own way. For the time being.

1. Rollbar

Dashboard Rollbar

They write on their website "Catch Errors if you can until the users did it for you. " Well, let's try. Rollbar provides a cloud service and is able to work with several programming languages ​​through the implantation of its SDK into a controlled application.

...
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## OpenSource APM Pinpoint

Kind to you.

Application performance monitoring (APM) solves the tasks of monitoring, managing the availability and performance of applications.

The pages of Habra already covered free AWP Glowroot and MoSKito , but here is Pinpoint remained in the shade.

Dynatrace - one of the innovators and leaders in the field of APM. The company had previously given the opportunity to use its product legally after a trial period.

Developers position Pinpoint as a tool for highly scalable distributed systems, which will allow you:

See the map and topology of the components ...
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## 1. What is Micronaut

Micronaut is a JVM framework for building lightweight modular applications. It was developed by OCI, the same company that Grails gave us. Micronaut is a modern framework designed to make the creation of microservice applications quick and easy.

Micronaut contains features similar to existing frameworks such as Spring, but at the same time it implements some new ideas that are its distinctive features. Together with the support of Java, Groovy and Kotlin, it offers many ways to create applications.

github.com/jreznot/micronaut-introduction ...[/h]
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## The book "Learning Java EE. Modern programming for large enterprises "

This book describes the new generation of Java EE. You will embark on a tour of Java EE in the context of the modern world of micro services and containers. This is not a reference manual for the syntax of the API - the concepts and techniques outlined here reflect the real experience of a person who himself recently passed this path, paying close attention to the obstacles encountered, and is ready to share his knowledge. In various situations, starting with the development of a package for testing and cloud-based use, this book will be an ideal companion for both beginners and experienced developers seeking ...
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