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Codetown is a software developer's community. It's a technical networking and educational group focused on software development.
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Issue 333 - Surprising += Cast (Rerun)
Surprisingly, the compound arithmetic expression contains a cast that can produce some interesting side effects. In this newsletter we explore this and other edge cases in the Java Language Specification.Issue 332 - ForkJoinPool.asyncCommonPool()
The common ForkJoinPool refuses to tell us its exact parallelism, in order to spare us embarrassing division by zero errors. The effect is that the rest of the concurrency framework has had to create dangerous workarounds to counteract a possibly zero sized pool. Since Java 25, the ForkJoinPool will silently create a couple of threads to make CompletableFuture (and others) safer to use. In addition, ForkJoinPool has become a ScheduledExecutorService, thus we can use the common ForkJoinPool as a global timer.Issue 331 - Virtual Thread States
No major feature has been adopted as quickly into production systems as virtual threads. Not generics. Not streams. But there are some catches. Original Java threads have six states. Virtual threads have 20 states, which Java maps onto the original six states. However, sometimes it can be useful to know what the virtual threads state is. In this newsletter we use deep reflection to learn how that works.Issue 330 - Looking Back on 25 Years
Today marks our 25th newsletter anniversary, when I sent out an email to 80 colleagues and friends. To celebrate, we are looking at some of the most popular newsletters over the years. Thanks for being part of this adventure.Issue 329 - Filtering Exceptions via try
One of the ways of figuring out the type of an exception is with instanceof. Another is to re-throw it, and to use the catch mechanism to sort things out. In this newsletter we look at different options, including switch with pattern matching.Birthdays
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New Java features
Posted by Michael Levin on August 29, 2025 at 5:32pm 0 Comments 0 Likes
August 28 2025, Newsletter no. 297 (this newsletter is available in html format at http://www.javaperformancetuning.com/news/news297.shtml )
As usual before a Java release, I'm listing all the new…
Free Eclipse book, recently published
Posted by Michael Levin on August 24, 2025 at 11:59am 0 Comments 0 Likes
ContinueHi Everyone,My publisher is running a free Amazon Kindle book promotion through Monday, August 25th, 2025. The book, “Eclipse Collections Categorically: Level up your programming game” can be obtained for $0 on Kindle on Amazon through the August 25th.…
What is vibe coding?
Posted by Michael Levin on June 9, 2025 at 9:37am 0 Comments 0 Likes
Vibe coding isn’t a formal technical term, but it’s become a slang or colloquial expression among programmers and tech communities—especially on social media and in creative coding circles.
What “vibe coding” usually means:
- Coding based on intuition or feel
Instead of rigidly planning everything out, you’re:- Freestyling as you…
You can now download the source code that sparked the AI boom
Posted by Michael Levin on March 25, 2025 at 4:30am 0 Comments 0 Likes
Learning about artificial intelligence? You may find this interesting.
https://arstechnica.com/ai/2025/03/you-can-now-download-the-source-code-that-sparked-the-ai-boom/
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Java SE Town
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Forum
Java books for any library 5 Replies
What books should be on the bookshelf of EVERY Java programmer, no matter what specific technologies they are working on?The two that come to my mind areThinking in JavaJava Concurrency in PracticeWhat else am I missing?Continue
Started by David Moskowitz in Java. Last reply by sneha gulati Feb 8, 2019.
Error trying to use Fragment
I am new to Android. I have been working thru some examples in a book called Head First Android Development. I entered a small program using fragments and get a Casting Error.cannot cast andoid.app.fragment to…Continue
Tags: Fragment
Started by Robert Sobol in Java Oct 10, 2017.
Fragment Syntax Problem
My name is Rob Sobol.I have been working through a book called Head First Android Development.I hit a syntax error in a simple exercise that uses one fragment. I have been trying to figure out the error for days. I am hoping some in the forum can…Continue
Tags: Fragments
Started by Robert Sobol in Java Oct 10, 2017.
Hadoop getting old?
An article just came out in InfoWorld about trends, which is always an interesting subject. Funny, they said Hadoop wasn't hot. Spark is. It's a good read. …Continue
Tags: codetown, infoworld, programming, hadoop, trends
Started by Michael Levin in Trends Apr 10, 2017.
What's functional programming, anyway?
Can you believe people are still trying to come up with a good definition or explanation of what functional programming is? Paul Krill is a journalist with InfoWorld. Here's an article he just wrote: …Continue
Tags: functions., codetown, lambdas, clojure, programming
Started by Michael Levin in Functional Programming Feb 21, 2016.
Santafe College 2 Replies
Santafe just added a new BAS bachelor's program of study. 5651 ProgrammingContinue
Started by Dan Lackey in Dynamic Languages. Last reply by Michael Levin Feb 15, 2016.
Using SQL with Node,.js 1 Reply
All the tutorials and books for node.js seem to use Mongo as the database. I am not sold on 'document' databases and would like to know how difficult it is to use any version for plain old tried-and-true SQL with Node.js.Does anybody have any…Continue
Tags: 'document, databases', SQL, node, node.js
Started by Kevin Neelands in Dynamic Languages. Last reply by Lou Caudell Nov 10, 2015.
The advantages of a RESTfull web-based API 5 Replies
I need to get a better handle on the advantages of a RESTful web-based API. People tell me they scale better than other methods, but I don't see how they reduce database access or have any other feature that helps handle large amounts of traffic.…Continue
Tags: API', 'web-based, RESTful
Started by Kevin Neelands in Dynamic Languages. Last reply by Kevin Neelands Oct 25, 2015.
Want a Job? 1 Reply
Hi, Not sure if this is the appropriate place to post this sort of things (forgive me if its not). My company (really nice company btw) is looking to hire two junior and two senior Java Developers. Please forward me your resume to slaassel@gmail.com…Continue
Started by Saad Laassel in Java. Last reply by Theresa Wizorek-MacIntyre Oct 15, 2014.
Storing Sensitive Data ( like SSNs ) 1 Reply
We might have to store Social Security Numbers. We REALLY don't want to do this in our own database, we'd like some external 'vault' service that stores them encrypted and getting to them is difficult. Does anyone have any ideas along these lines?Continue
Started by Kevin Neelands in Java. Last reply by Michael Levin May 7, 2014.
Latest Activity
Ever wondered how companies gauge customer interest? Discover the surprising tactics from Expedia...
In an intriguing throwback, key insights from the life of Dara Khosrowshahi unveil how seemingly ineffective strategies, like implementing a non-functioning ...
"Thanks Mike! What a blast from the past! That Red Hat swag! ;-). Jim"
Dev2Next at Colorado Springs Marriott
September 29, 2025 at 6pm to October 1, 2025 at 7pm
It's hard to believe, but we're in the last few weeks heading up to the dev2next 2025 conference. I'm eager to welcome speakers and attendees at the event. The Near Time Registration is open for those who have been waiting to get their final approvals to attend. Hotel rooms reserved, flights booked, meals planned, swags ordered (did I say swags), I can't wait for the…See More
New Java features
August 28 2025, Newsletter no. 297 (this newsletter is available in html format at http://www.javaperformancetuning.com/news/news297.shtml )As usual before a Java release, I'm listing all the new performance features in the upcoming release, this time for Java…See More
Happy 10th year, JCertif!
Notes
Welcome to Codetown!
Codetown is a social network. It's got blogs, forums, groups, personal pages and more! You might think of Codetown as a funky camper van with lots of compartments for your stuff and a great multimedia system, too! Best of all, Codetown has room for all of your friends.
When you create a profile for yourself you get a personal page automatically. That's where you can be creative and do your own thing. People who want to get to know you will click on your name or picture and…
ContinueCreated by Michael Levin Dec 18, 2008 at 6:56pm. Last updated by Michael Levin May 4, 2018.
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InfoQ Reading List
Discord Engineers Add Distributed Tracing to Elixir's Actor Model Without Performance Penalty
Discord engineering detailed how they added distributed tracing to Elixir's actor model. Their custom Transport library wraps messages with trace context and uses dynamic sampling to handle million-user fanouts. CPU optimizations included skipping unsampled traces and filtering context before deserialization, recovering 10+ percentage points of overhead.
By Steef-Jan WiggersHashiCorp Vault 1.21 Brings SPIFFE Authentication, Granular Secret Recovery, and More
HashiCorp has released Vault 1.21. This version introduces native SPIFFE authentication for non-human workloads, expands the granular secret recovery model introduced in Vault 1.20, and adds KV v2 secret attribution, MFA TOTP self-enrollment, a Vault Secrets Operator CSI driver that mounts secrets directly into pods without persisting them in etcd, and more.
By Diogo Carleto"Pick and Mix" Custom Regions: Cloudflare Introduces Fine-Grained Data Residency Control
Cloudflare recently introduced Custom Regions, an expansion of its Regional Services that lets customers precisely define where their data is processed. By selecting specific groups of data centers by country or region, customers can ensure that TLS termination and application-layer processing remain within chosen geographic boundaries for compliance and control.
By Renato LosioExperimental Web Install API Seeks to Improve Application Discovery and Distribution
The new, experimental Web Install API is now in Origin Trial in Microsoft Edge and Chrome. The API allows developers to programmatically trigger a PWA installation prompt from in-app user interactions. The API aims to simplify software discovery and distribution, particularly for users who are unaware of the install icon in the browser’s address bar or do not typically use app stores.
By Bruno CouriolQCon London 2026: AI Agents Write Your Code. What’s Left For Humans?
Hannah Foxwell began her QCon London 2026 talk by noting that the long-sought velocity in development has arrived, but the industry is unsure how to use it. She set aside the technical details of agentic coding, focusing instead on its implications for the people working with these systems.
By Matt Saunders
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