Excell files circulate in the veins of large companies. Ther are times when you want to extract some data and you have to use Java language for this purpose. Let’s see how to quickly extract data from .xls or .xlsx files using Apache POI library.

The library

Maven coordinates of the library(ies) can be found here: https://mvnrepository.com/artifact/org.apache.poi. Note that there are two types of excel spreadsheet formats and apache-poi project has two of its most important libraries to handle these data:

I registered in ChatGPT web page today. Here are my prompts and its responses. I’m not very creative, as you can see. Perhaps I don’t have enough faith in its capabilities to expect more than from a better search engine.

Images in today’s blog post are generated using http://bing.com/images/create

Generate blog post

Generate blogpost about chat gpt written by a programmer about capabibities and risks related with AI usage when programming.

Notes about asynchronous programing in Dart. In this article I test and learn about two variants of writing asynchronous code in Dart: async/await and Future-based.

Welcome in a new series of articles about Dart programming language.

It is not a beginner tutorial. I focus mainly on features that may be surprising and/or interesting for a Java(Script) developer.

Slides

Slide notes are available here.

The resources:

Start with these:…

1. https://dart.dev/guides/language/language-tour (language overview)
2. https://dartpad.dev/ (write & run in online editor)
3. https://dart.dev/guides/language/spec (language specification page, current spec pdf: 2.10)
4. https://dart.dev/guides/language/effective-dart (good practices)

Basics

… or look below:

Java predictions

Predictions by authors of Java JVM Trends focus on faster adoption of new Java features and long-term releases

• frameworks (Helidon, Vert.x etx.) start providing Virtual Threads programming models, so the usage of this language/platform feature would grow
• native Java could become more visible due to Project Leyden (back to life in 2022) and focus on ease of use for Spring developers
• migration from MicroProfile Metrics to metrics and tracing by Micrometer.
• frameworks set the baseline to Java 17 (Spring)
• Java 11 takes over Java 8 (market): needs modernization of old stacks (libs, dependencies), challenge for many Java developers
• adoption of Java 17 is faster than Java 11
• Java as a language is strong (Jetbrains dev ecosystem research from 2021, waiting for 2022 one)

Resources

• https://www.infoq.com/articles/java-jvm-trends-2022/
• https://newrelic.com/resources/report/2022-state-of-java-ecosystem
• https://www.jetbrains.com/lp/devecosystem-2021/
• https://openjdk.org/projects/leyden/notes/01-beginnings

IT predictions

• more focus on security
• recognition for core value of IT Ops / Dev Ops
• Amazon (or: Cloud) rising even more
• optimization of development, processes, libraries in the direction of
  • containers
  • CI/CD
• more impact of developers and engeneers on company-level decision making
• no-code is not a threat for developers
• GPT-4 would be a game-changer; robotics will go mainstream expected adoption of self-driving cars
• buzzing in social platforms (Twitter, Tik-Tok), possible further content-moderation regulatory actions (esp. in Europe)
• new trends: IoB (Internet of Behaviour) - analysis of human behaviour with analytics (security issues) and prediction of futire behavior

Resources

• https://www.ipsos.com/en/ipsos-global-predictions-2023
• https://enterprisersproject.com/article/2022/12/tech-predictions-2023
• https://www.forbes.com/sites/robtoews/2022/12/20/10-ai-predictions-for-2023/
• https://www.theverge.com/2022/12/16/23512588/tech-platform-predictions-2023-facebook-twitter-moderation
• https://trojanczyk.eu/internet-of-behaviour-iob-what-it-is-data-predictions-and-benefits-for-business-and-threats-to-private-life/

What I think

I’m reading about the trends in IT and expected directions for companies, inverstors and business in IT world and one theme comes again and again as a common denominator of all the predictions. This theme is: the client. But we as individuals are not “the client”: we are “the revenue stream”. The real client (the one who gives money to software companies) wants the information and needs software professionals to dig that information in order to know:

In this article I’m going to explore what an API is, why we might want to change it, how to do it and how to do it safely.

Task appropriate for the job

• high parallelization : use fork-join pool and and parallel streams for highly CPU-bound calculations
• high interactivity: high concurrency and a need to keep a lot of IO-bound tasks on single CPU: use Future (Completable Future) or Flow API

Problems and solutions

Threads problems

• map 1:1 to OS threads (expensive to create and of limited number)
• much higher number than hardware threads (cores? well, it seems a core is more complex)

CPUs like the Intel i7-6900K have multiple hardware threads per core, so the CPU can execute useful instructions even for short delays such as a cache miss.

Chapter 14 is “The Java Module System” and this post is a note that helps to refresh my knowledge about Java Module System.