Simon Willison's Weblog: java

firefox parser/html/java/README.txt

2025-12-17T01:48:54+00:00

TIL (or TIR - Today I was Reminded) that the HTML5 Parser used by Firefox is maintained as Java code (commit history here) and converted to C++ using a custom translation script.

You can see that in action by checking out the ~8GB Firefox repository and running:

cd parser/html/java
make sync
make translate

Here's a terminal session where I did that, including the output of git diff showing the updated C++ files.

I did some digging and found that the code that does the translation work lives, weirdly, in the Nu Html Checker repository on GitHub which powers the W3C's validator.w3.org/nu/ validation service!

Here's a snippet from htmlparser/cpptranslate/CppVisitor.java showing how a class declaration is converted into C++:

    protected void startClassDeclaration() {
        printer.print("#define ");
        printer.print(className);
        printer.printLn("_cpp__");
        printer.printLn();

        for (int i = 0; i < Main.H_LIST.length; i++) {
            String klazz = Main.H_LIST[i];
            if (!klazz.equals(javaClassName)) {
                printer.print("#include \"");
                printer.print(cppTypes.classPrefix());
                printer.print(klazz);
                printer.printLn(".h\"");
            }
        }

        printer.printLn();
        printer.print("#include \"");
        printer.print(className);
        printer.printLn(".h\"");
        printer.printLn();
    }

Here's a fascinating blog post from John Resig explaining how validator author Henri Sivonen introduced the new parser into Firefox in 2009.

Via Hacker News conversation

Tags: c-plus-plus, firefox2, henri-sivonen, java, john-resig, mozilla

Java in the Small

2024-12-18T21:20:11+00:00

Java in the Small

Core Java author Cay Horstmann describes how he now uses Java for small programs, effectively taking the place of a scripting language such as Python.

TIL that hello world in Java can now look like this - saved as hello.java:

void main(String[] args) {
    println("Hello world");
}

And then run (using openjdk 23.0.1 on my Mac, installed at some point by Homebrew) like this:

java --enable-preview hello.java

This is so much less unpleasant than the traditional, boiler-plate filled Hello World I grew up with:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

I always hated how many concepts you had to understand just to print out a line of text. Great to see that isn't the case any more with modern Java.

Via Hacker News

Tags: java

Quoting Andy Jassy

2024-08-24T04:25:06+00:00

[...] here’s what we found when we integrated [Amazon Q, GenAI assistant for software development] into our internal systems and applied it to our needed Java upgrades:

The average time to upgrade an application to Java 17 plummeted from what’s typically 50 developer-days to just a few hours. We estimate this has saved us the equivalent of 4,500 developer-years of work (yes, that number is crazy but, real).

In under six months, we've been able to upgrade more than 50% of our production Java systems to modernized Java versions at a fraction of the usual time and effort. And, our developers shipped 79% of the auto-generated code reviews without any additional changes.

— Andy Jassy, Amazon CEO

Tags: ai-assisted-programming, amazon, generative-ai, ai, llms, java

Queryable Logging with Blacklite

2023-08-21T18:13:35+00:00

Queryable Logging with Blacklite

Will Sargent describes how he built Blacklite, a Java library for diagnostic logging that writes log events (as zstd compressed JSON objects) to a SQLite database and maintains 5,000 entries in a “live” database while entries beyond that range are cycled out to an archive.db file, which is cycled to archive.timestamp.db when it reaches 500,000 items.

Lots of interesting notes here on using SQLite for high performance logging.

“SQLite databases are also better log files in general. Queries are faster than parsing through flat files, with all the power of SQL. A vacuumed SQLite database is only barely larger than flat file logs. They are as easy to store and transport as flat file logs, but work much better when merging out of order or interleaved data between two logs.”

Via asgi-log-to-sqlite/issues/1

Tags: java, logging, sqlite, zstd

Are traditional web frameworks and languages like RubyOnRail, Spring Boot and PHP dying now when new fast reactive pure JavaScript frameworks and services like Meteor, Node, Angular 2.0 and Firebase are breaking ground?

2015-05-24T09:33:00+00:00

My answer to Are traditional web frameworks and languages like RubyOnRail, Spring Boot and PHP dying now when new fast reactive pure JavaScript frameworks and services like Meteor, Node, Angular 2.0 and Firebase are breaking ground? on Quora

No.

Tags: django, frameworks, java, javascript, programming, programming-languages, web-development, quora

Why doesn't Google use their resources to improve coding languages?

2013-11-24T17:31:00+00:00

My answer to Why doesn't Google use their resources to improve coding languages? on Quora

Google invest vast resources in to language improvements, and have been doing so for over a decade now. Just off the top of my head...

They have employed many of the Python core team (including creator Guido van Rossum) and supported their work on Python
Their Android team wrote and support an entirely new open source JVM, called Dalvik
They sponsored one of the creators of C to create a brand new systems programming language, Go.
They sponsored major improvements to HTML, including the WHAT-WG which was crucial to the creation of HTML5.
Many of their employees work full time contributing to international standards groups.
As part of Chrome they supported the creation of V8, an astonishingly powerful JIT JavaScript implementation which sparked enormous improvements across rival engines. V8 is also the core of Node.js
Through Google Summer of Code they financially support projects that benefit dozens of open source languages, libraries and frameworks

That's just the stuff I can think if without doing any additional research - it's the tip of the iceberg.

Tags: google, java, programming, programming-languages, web-development, quora

Does it still make sense to become a Java developer, or should I migrate to PHP or .NET?

2013-01-30T13:52:00+00:00

My answer to Does it still make sense to become a Java developer, or should I migrate to PHP or .NET? on Quora

It sounds like you need to expand your horizons a little further. The best programmers I know these days aren't working solely in Java, PHP or .NET - they may use one those languages, but they'll also be getting stuck in to dynamic languages such as Python, Ruby, JavaScript or Scala.

If you take a look at the most popular languages for projects on GitHub you'll see that JavaScript and Ruby are in the lead, with Python neck-and-neck with Java and PHP in 6th place: Top Languages · GitHub

Here's a general piece of career advice: try to avoid thinking of yourself as a "Language X programmer". Learning new languages is a great way of improving your skill as a programmer - learning Python will also have a big effect on how you program in C# or Java for example. The best programmers can pick up pretty much any language in a couple of weeks.

It's also worth focusing on picking up related skills: SQL, HTML, unix administration, web security, network programming and version control for example. All of these are skills that will greatly enhance your career and help you land the most interesting development jobs.

Tags: java, programming, web-development, quora, careers

What is the easiest server-side platform for Android Java developers to learn?

2012-12-04T17:10:00+00:00

My answer to What is the easiest server-side platform for Android Java developers to learn? on Quora

Take a look at the Play framework - last time I looked (a couple of years ago) it seemed to be the most instant productive and sane way of doing server-side Java.

Tags: android, frameworks, java, quora

Can Scala gain wider usage than Java any time soon?

2012-02-11T17:17:00+00:00

My answer to Can Scala gain wider usage than Java any time soon? on Quora

No, because Scala is harder to master than Java.

(By "master" I mean get to the point where you can read and understand code written by someone else, no matter what language features and idioms they are using)

Tags: concurrency, java, programming, scala, scaling, web-development, quora

Where can I find great Java/Scala developers in London?

2012-01-22T10:36:00+00:00

My answer to Where can I find great Java/Scala developers in London? on Quora

There are quite a few Scala events in London - here are the ones we know about at the moment: http://lanyrd.com/topics/scala/i...

The Scala Days conference at the Barbican in April looks like a particularly good place to find Scala developers. Since it's still a relatively niche language I imagine there are a bunch of Java developers who would like the opportunity to work with it full time.

Tags: java, london, recruiting, scala, quora

Which web frameworks should I focus on to make myself the most well rounded and to be able to solve the most problems as a web application developer/architect?

2012-01-18T17:17:00+00:00

My answer to Which web frameworks should I focus on to make myself the most well rounded and to be able to solve the most problems as a web application developer/architect? on Quora

Being an expert web developer isn't about which framework you know, it's about the fundamentals. It's important that you know how the tools you are using work, so you can fix things when they break - Joel Spolsky's law of leaky abstractions is a great essay about this: http://www.joelonsoftware.com/ar...

So pick a modern framework, but make sure you're learning how web technology works. You need to understand all aspects of HTTP, including cookies, caching, content negotiation etc. You need to understand web application security: XSS, CSRF, the OWASP top ten. You need a very solid appreciation of front end development technologies - CSS, HTML, JavaScript - even if you don't specialise in front end engineering most backed decisions you make need to take these in to account.

Then there are the systems architecture concerns: persistence, sharing, replication, when and where to apply both SQL and NoSQL technologies, load balancing and so forth.

The web framework you use ends up being a relatively small part of the overall problem - it's just the bit that passes an incoming HTTP request through to your custom code, then hands the resulting response back again.

So as long as you pick something that doesn't prevent you from getting stuck in to the underlying details (a closed source framework would be a bad idea here) you should be fine.

Tags: frameworks, java, programming-languages, software-engineering, web-development, quora, ecommerce, hibernate

What are the most practical beneficials for Python, comparing to Java?

2011-12-30T18:15:00+00:00

My answer to What are the most practical beneficials for Python, comparing to Java? on Quora

For me, the single most productive advantage of Python is the ability to work with it interactively in a REPL - I use ipython but Python also ships with an interactive mode out of the box.

I do almost all of my development in the interactive prompt first, then copying working code in to a text editor once I've got it working interactively.

I find this more than compensates for the lack of an auto-completing IDE such as Eclipse - in fact ipython does both autocompletion and offers inline documentation (just type symbol? and hit enter for the signature/docstring or symbol?? for the source code to a function).

Once you've learnt to develop interactively in this way it can be really frustrating working with a language like Java or PHP that doesn't lend itself effectively to this style of programming.

I use Firebug and similar tools in the browser to gain the same development style for working with JavaScript.

Tags: java, python, quora

Quoting Brian Goetz

2011-08-19T12:20:00+00:00

There is plenty of evidence in the ecosystem to support the hypothesis that, if given the tools to do so easily, object-oriented programmers are ready to embrace functional techniques (such as immutability) and work them into an object-oriented view of the world, and will write better, less error-prone code as a result. Simply put, we believe the best thing we can do for Java developers is to give them a gentle push towards a more functional style of programming.

— Brian Goetz

Tags: functional-programming, java, recovered

Why does Java encourage over-engineering?

2010-11-16T13:06:00+00:00

My answer to Why does Java encourage over-engineering? on Quora

I suggest reading "Execution in the Kingdom of Nouns" http://steve-yegge.blogspot.com/...

Tags: java, quora

Why is Java perceived as not cool for startups? We seem to be getting a lot of feedback lately that a startup should be using Ruby on Rails, PHP, Python, etc., if they want to be agile and iterate quickly.

2010-11-14T12:21:00+00:00

My answer to Why is Java perceived as not cool for startups? We seem to be getting a lot of feedback lately that a startup should be using Ruby on Rails, PHP, Python, etc., if they want to be agile and iterate quickly. on Quora

I believe what takes the longest time in software engineering is not actually writing the code, but untangling it to find bugs, and Java is much more conducive to that, and the tooling is much stronger than for other languages.

You should re-evaluate your beliefs. Dynamic language programmers spend a great deal of time thinking about code quality and maintainability. TDD (and BDD), which I believe was first popularised within the Ruby community) are extremely widespread, and profiling and debugging tools are widely used and constantly improved. A strong test suite provides far more effective protection against bugs than static typing and an IDE.

Tags: java, programming, programming-languages, rails, startups, static-typing, quora, careers

What are the main weaknesses of Java as a programming language?

2010-10-15T14:25:00+00:00

My answer to What are the main weaknesses of Java as a programming language? on Quora

A cultural bias towards over-engineering. In my experience Java code often ends up a huge network of Factories and AbstractFactories and Visitors and XML configuration files and every design pattern you care to mention, dozens of classes many of which contain hardly any procedural code at all. A lot of Java projects are essentially impossible to navigate without an IDE.

Tags: design-patterns, java, programming-languages, quora

Why don't more people use Google Web Toolkit for web development as opposed to scripting alternatives like JavaScript?

2010-10-12T18:28:00+00:00

My answer to Why don't more people use Google Web Toolkit for web development as opposed to scripting alternatives like JavaScript? on Quora

I'm morally opposed to GWT, because I don't believe in building sites or applications that are entirely dependent on JavaScript to function. As someone who took the time to learn JavaScript, I'm also not at all convinced that Java is a more productive language.

Tags: frameworks, gwt, java, javascript, quora

Creating Shazam in Java

2010-09-22T21:39:00+00:00

Creating Shazam in Java

Using a Fast Fourier Transformation.

Tags: algorithms, java, recovered, shazam

Quoting Rafe Colburn

2010-04-10T18:42:31+00:00

We all think of Java as a boring server-side language now, but the initial idea behind Java was that software developers could write applications in Java rather than writing them for Windows, and that those applications would work everywhere, thus defanging Microsoft’s desktop OS monopoly. Microsoft took various steps to prevent that from happening, but they lacked a tool like App Store that would enable them to just ban Java. Apple has that card to play, so they’re playing it.

— Rafe Colburn

Tags: microsoft, apple, java, iphone, appstore, rafe-colburn

ElasticSearch: Your Data, Your Search

2010-02-12T15:22:09+00:00

ElasticSearch: Your Data, Your Search

A neat example of how ElasticSearch’s schemaless indexes and native JSON support make it ridiculously easy to index different types of data and run queries across them.

Tags: elasticsearch, java, json, schemaless, search

Elastic Search

2010-02-11T18:33:14+00:00

Elastic Search

Solr has competition! Like Solr, Elastic Search provides a RESTful JSON HTTP interface to Lucene. The focus here is on distribution, auto-sharding and high availability. It’s even easier to get started with than Solr, partly due to the focus on providing a schema-less document store, but it’s currently missing out on a bunch of useful Solr features (a web interface and faceting are the two that stand out). The high availability features look particularly interesting. UPDATE: I was incorrect, basic faceted queries are already supported.

Via ElasticSearch blog

Tags: elasticsearch, http, java, json, lucene, rest, scaling, search, sharding, solr

Quoting Glitch

2010-02-10T11:40:44+00:00

Glitch is built in an entirely new and different way for a game. The back end (java at the lowest level, with game logic scripted in Javascript) is designed for maximum flexibility and ease of deployment. That means we'll be able to push new content — new items, new places, new characters — on a daily basis. It also means that we'll have lots of APIs with which the game can be expanded and extended.

— Glitch

Tags: glitch, java, javascript, rhino

twitter-text-conformance

2010-02-06T15:39:27+00:00

twitter-text-conformance

This is a neat idea: Twitter have released open source libraries for parsing standard tweet syntax in Ruby and Java, but they’ve also released a set of YAML unit tests aimed at anyone who wants to implement the same parsing logic in other languages.

Via Twitter Engineering Blog

Tags: java, ruby, testing, twitter, yaml, conformance-suites

Plurk: Instant conversations using Comet

2010-02-01T10:13:14+00:00

Plurk: Instant conversations using Comet

Plurk’s comet implementation sounds pretty amazing. They’re using a single quad-core server with 32GB of RAM running 8 Node.js instances to serve long-polled comet to 100,000+ simultaneous users. They switched to Node from Java JBoss/Netty and found the new solution used 10 times less memory.

Via Hacker News

Tags: comet, java, javascript, jboss, netty, nodejs, plurk

Frank Wierzbicki: Leaving Sun

2009-11-04T22:33:05+00:00

Frank Wierzbicki: Leaving Sun

Frank performed miracles at Sun and before, helping bring the Jython project out of stasis and turning it in to an active, community maintained modern Python implementation. If you’re looking for an expert Python/Java/Dynamic languages guy you should snap him up.

Tags: frank-wierzbicki, java, jython, python, sun

Play framework for Java

2009-10-25T23:21:36+00:00

Play framework for Java

I’m genuinely impressed by this—it’s a full stack web framework for Java that actually does feel a lot like Django or Rails. Best feature: code changes are automatically detected and reloaded by the development web server, giving you the same save-and-refresh workflow you get in Django (no need to compile and redeploy to try out your latest changes).

Tags: django, frameworks, java, play, rails, web

Introducing Cloudera Desktop

2009-10-21T18:48:36+00:00

Introducing Cloudera Desktop

It’s a GUI for Hadoop, and under the hood is a whole stack of open source software, including Python, Django, MooTools, Twisted, lxml, CherryPy, Mako, Java and AspectJ.

Tags: aspectj, cherrypy, cloudera, django, hadoop, java, lxml, mako, mootools, open-source, python, twisted

And so it goes, around again

2009-09-03T09:46:33+00:00

And so it goes, around again

Charles Miller on Java, pointing out that if you don’t have closures and first-class functions you end up having to add band-aid solutions and special case syntactic sugar. Python’s lack of multi-line lambdas leads to a similar (though less pronounced) effect.

Tags: charles-miller, closures, java, programming-languages, python

Scriptlets - Quick web scripts

2009-08-13T13:51:10+00:00

Scriptlets - Quick web scripts

From the prolific Jeff Lindsay, a pastebin-style tool for short server-side scripts written in Python, JavaScript or PHP that executes them within a Google App Engine powered sandbox. The Java code that implements the service is available on GitHub.

Via Easy hook scripts with Scriptlets

Tags: github, google-app-engine, java, javascript, jeff-lindsay, open-source, php, python, scriptlets, webhooks

Jython 2.5.0 Final is out!

2009-06-16T23:21:07+00:00

Jython 2.5.0 Final is out!

It’s been a long time coming—congratulations to the team.

Tags: java, jython, python