Headius: My Favorite Hotspot JVM Flags
http://blog.headius.com/2009/01/my-favorite-hotspot-jvm-flags.html

parámetros de la bazofia de la máquina virtual del puto java

Clojure is a LISP implementation for the Java Virtual Machine.

"The goal of this article is to provide a fairly comprehensive introduction to the Clojure programming language."

# nt a better summary of heap statistics. # Sort objects by retained heap. In other words, some tools can tell you the memory usage of an object and all other objects that are referenced by it, as well as list the objects referenced by other objects. This makes it much faster to diagnose the cause of a memory leak.

How to Fix Memory Leaks in Java | Javalobby

thorough tutorial on identifying and fixing memory leaks, focused on Java

Fix Memory

great bookmarks

How to Fix Memory Leaks in Java

g system, mobile platform, or web platform. Basically, if you want to share a short thought, one to many, Twitter is a transport-independent way to do that. In a broader technical sense, we see ourselves as a short messaging layer for the internet. We’ve been described as a “telegraph for web 2.0.” One of the things that’s core to our business is providing open APIs for everything you can do on the website. So all the functionality that’s available there for users is also available for developers to access programmatically. That’s Twitter in a nutshell. Twitter started as a hack project at a company called ODEO, which was focused on podcasting. As ODEO was having some troubles in its latter days as a company, they started experimenting, to keep engineers involved by letting them play around with ideas they had on the side. One of the engineers, Jack Dorsey, had been really interested in status. He was looking at his AIM buddy list, and seeing that all of these guys were saying, “I’m w

How twitter uses scala to gain performance and stability

tags: scala twitter ruby programming scalability interview rails

"Steve Jenson: For example, if you make a change to your social graph; i.e., you follow or unfollow someone on Twitter. All of that work and the associated cache invalidations are done asynchronously by a daemon."

Three Twitter developers, Steve Jenson, Alex Payne, and Robey Pointer, talk with Bill Venners about their use of Scala in production at Twitter.

In this post I thought I’d go through the steps you need to take to get a JRuby on Rails application working on GAE/J, and also what kind of characteristics you should expect from your application.

JRuby on RailsをApp Engine上で動かす方法

This article explains what native memory is, how the Java runtime uses it, what running out of it looks like, and how to debug a native OutOfMemoryError on Windows® and Linux®

Clojure - Functional Programming for the JVM

Clojure is a functional programming language for the Java Virtual Machine with several powerful features for building concurrent applications. In addition, Clojure is fast, robust, and a powerful general-purpose programming language. A dialect of Lisp, Clojure embraces traditional code-as-data philosophy and a powerful macro system, plus some syntactic sugar tailored to Java.

rphism across strings/text/buffers/collections/arrays along with extremely verbose syntax for working with any kind of data structure

via @indrayam FF post

Scala as the long term replacement for java/javac?

Clojure is surrounded by hype these days. The word on the streets is that Clojure is the Next Big Thing. It has access to the largest library of code and it proposes a nice solution the to the concurrency problem. Lots more has been said... But I haven't seen a lot of code. So I set out to make a small but meaningful program in Clojure to get a sense of it's potential. I give Clojure two thumbs up, and I think you'll do too. The Mona Lisa Problem The program I present tries to paint Mona Lisa with a small number of semi-transparent colored polygons. It does so by using Darwin's theory of evolution to evolve programs that draw Mona Lisa.

The (clojure) program I present tries to paint Mona Lisa with a small number of semi-transparent colored polygons. It does so by using Darwin's theory of evolution to evolve programs that draw Mona Lisa.

Software Transactional Memory

http://queue.acm.org/detail.cfm?id=1454466

Cliff Click Jr.’s Blog

I just foolishly got caught in a You-Tube discussion on Java vs C performance. Foolish because You-Tube comments are a lousy way to present anything and because it's hard to keep the level of discourse scholarly. And foolish especially for me because I've had this discussion so many times and it always comes out the same way... so here's my attempt at distilling my arguments into something I can point people the *next* time I get caught in this silly discussion. Is Java faster than C/C++? The short answer is: it depends.

An article describing the basic syntax of clojure

In this article, you will see some of the ways that Clojure addresses the key concerns of OO: encapsulation, polymorphism, and inheritance.

JVM-based, Java-like language with dependency injection.

NOPかと思った。何もしないのかと

library

Noop (pronounced noh-awp, like the machine instruction) is a new language experiment that attempts to blend the best lessons of languages old and new, while syntactically encouraging industry best-practices and discouraging the worst offenses. Noop is initially targeted to run on the Java Virtual Machine.

Clojure is a LISP for the JVM created by Rich Hickey.

FlightCaster, a realtime flight delay site, is built on Clojure and Hadoop for the statistical analysis. The web frontend is built with Ruby on Rails and hosted on Heroku. We talked to Bradford Cross about Clojure, functional programming and tips for OOP developers interested in making the jump.

Another critical piece of infrastructure is Cascading; an excellent layer on top of Hadoop that adds additional abstraction and functionality. We definitely recommend Cascading to anyone doing serious data processing and mining with Hadoop.

Sun now integrates a profiler in the jdk

Java VisualVM – Developer`s Nightmare is Over

VisualVM is an open source tool for monitoring and profiling your Java applications. VisualVM is now integrated with JDK 6 update 7 release and also available as a stand-alone setup. Java 7 plans to integrate next version 1.2.

Rails

"Twitter jilts Ruby for Scala" - Alex Payne http://tr.im/i7Vb [from http://twitter.com/kenmat/statuses/1436463196]

In this presentation from the JVM Languages Summit 2009, Cliff Click discusses the Von Neumann architecture, CISC vs RISC, the rise of multicore, Instruction-Level Parallelism (ILP), pipelining, out-of-order dispatch, static vs dynamic ILP, performance impact of cache misses, memory performance, memory vs CPU caching, examples of memory/CPU cache interaction, and tips for improving performance. -- It's a shame I would of liked to see the presentation on their hardware transactional memory implementation and why "it doesn't work as all the academics would have you believe."

In this presentation from the JVM Languages Summit 2009, Cliff Click discusses the Von Neumann architecture, CISC vs RISC, the rise of multicore, Instruction-Level Parallelism (ILP), pipelining, out-of-order dispatch, static vs dynamic ILP, performance impact of cache misses, memory performance, memory vs CPU caching, etc.

In the first half of his introduction to actor concurrency, Alex Miller discussed the limitations of shared-state concurrency and explained how the actor model is expressed in Erlang. While Erlang is a nonstarter for many shops, actor implementations do exist for languages that run on the JVM. Find out how actors work and see them implemented using Scala's standard library, Groovy's GParallelizer, and the Java libraries Kilim, ActorFoundry, Actors Guild, and Jetlang.

"These two seem like an interesting combination. Imagine the possibilities...kill your database, simple POJO applications, free distributed transactions, clustered JVMs with limitless memory...it would make your hair would grow back, you'd get women, and become filthy rich...well...maybe not, but at least you'd have more fun writing software." -- Paul Stadig

You don't need to debug Java applications on just your local desktop. Learn how to spread around your debugging using different connection types that make up remote debugging. This article outlines the features and examples that show how to set up remote application debugging.

Remote Debugging of JAVA Applications

Java Platform (AKA, JVM) library/framework for distributed, fault-tolerant system through Actors. Scala and Java APIs. Found through Dean Wampler. Project tag line is "Simpler Scalability, Fault-Tolerance, Concurrency & Remoting through Actors"

Simpler Scalability, Fault-Tolerance, Concurrency & Remoting through Actors (Erlang con API Java e Scala)

physical

Useful, in-depth discussion of how memory is handled on Windows and Linux with respect to Java Virtual Machines. How to diagnose memory problems; dealing with Java heap as well as native memory exhaustion issues. Source code / demo

Processors are described as being a certain number of bits. This normally refers to the size of the registers, although there are exceptions — such as 390 31-bit — where it refers to the physical address size. For desktop and server platforms, this number is 31, 32, or 64; for embedded devices and microprocessors, it can be as low as 4. The physical address size can be the same as the register width but could be larger or smaller. Most 64-bit processors can run 32-bit programs when running a suitable OS.

XML example

Shows good examples of XML and HTTP processing in Clojure

X# (pronounced X-sharp) is a domain specific language designed to quickly create Web applications and services. In X# everything is represented as a hierarchical structure or tree and instead of using functions to manipulate information or perform actions, all possible operations you can think of are done by adding, removing or changing nodes from this tree. Since there are no functions to learn and everything is done intuitively, even inexperienced developers can create complex Web applications and services in record time.

X# (pronounced X-sharp) is a domain specific language designed to quickly create Web applications and services. In X# everything is represented as a hierarchical structure or tree and instead of using functions to manipulate information or perform actions, all possible operations you can think of are done by adding, removing or changing nodes from this tree.

Web application and services domain specific language

I have chosen four languages which together represent "Java.next": Clojure, Groovy, JRuby, and Scala. Notes on Functional programming

Annotated link http://www.diigo.com/bookmark/http%3A%2F%2Fblog.thinkrelevance.com%2F2008%2F8%2F4%2Fjava-next-common-ground

This sentence from the article says much: "In my experience, this style of coding tends to reduce the size of a codebase by an order of magnitude, while improving readability." Example from article: "...do not have to code defensively, using a slew of factories, patterns,...you can build a minimal solution and evolve it."

"Many people are looking for the "next big language." The next big language is already here, but it isn't a single language. It is the collection of ideas above (plus probably some I missed) as manifested in Java.next. -- Does the transition to Java.next deserve the name "big"? Absolutely. In my experience, the move from Java to Java.next is every bit as big as the previous tectonic shifts in the industry, both in learning curve and in productivity advantages once you make the transition."

via http://news.ycombinator.com/item?id=1426799 + http://www.reddit.com/r/programming/comments/cejxa/scala_for_hackers/

Foursquare

Formerly PLT/Dr Scheme

With Racket, you can script command shells and web servers; you can quickly prototype animations and complex GUIs; regexps and threads are here to serve you. To organize your systems, you can mix and match classes, modules or components. Best of all, you start without writing down types.