Blogmarks tagged java
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Java in the Small (via) 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.
Queryable Logging with Blacklite (via) 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.”
Creating Shazam in Java. Using a Fast Fourier Transformation.
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.
Elastic Search (via) 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.
twitter-text-conformance (via) 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.
Plurk: Instant conversations using Comet (via) 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.
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.
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).
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.
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.
Scriptlets—Quick web scripts (via) 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.
Jython 2.5.0 Final is out! It’s been a long time coming—congratulations to the team.
Critical Mac OS X Java Vulnerabilities. There’s a five month old Java arbitrary code execution vulnerability which hasn’t yet been patched by Apple. Disable Java applets in your browser until it’s fixed, or random web pages could execute commands on your machine as your user account.
oauth-signpost. The Qype API uses OAuth to sign client requests with the developer’s API key, so it’s not surprising to see them release a Java OAuth signing library compatible with Google’s Android mobile platform.
Using Scala with Google App Engine. Scala works, but I haven’t seen confirmation on actors yet (which are likely to break due to their dependency on threads).
Dynamic languages on Google App Engine—an overview. Ola Bini’s notes on exploring the new Java support for App Engine with the aim of getting JVM dynamic languages such as JRuby running. Restrictions include a complete lack of threads (which will make it hard to get Scala up and running), but JRuby trunk now works without modification.
Heap Dump Analysis. Using jmap to dump the JVM’s memory to disk, then analysing it using the visualvm GUI tool.
Magic properties make Firefox synchronously load the Java plugin. Even defining a function called sun() (or several other symbols) will trigger the Java VM to be loaded, dramatically hurting the performance of your page.
CloudMade: A Summary of the Future of Mapping. CloudMade are now offering commercially supported APIs on top of OpenStreetMap, including geocoding, routing and tile access libraries in Python/Ruby/Java and a very neat theming tool that lets you design your own map styles. This is really going to kick innovation around OpenStreetMap up a notch.
Apache Qpid. A new open source AMQP message queue with implementations in C++ and Java, developed by engineers from Red Hat, IONA and JP Morgan Chase. Anyone tried this yet? Looks pretty good on paper.
Sloppy—the slow proxy. Java Web Start GUI application which runs a proxy to the site of your choice simulating lower connection speeds—great for testing how well your ajax holds up under poor network conditions.
“By installing Java, you will be able to experience the power of Java”. Wow, that’s some bad copy.
How we use IRC at Last.fm. With IRCCat, an elegant Java IRC bot that accepts Twitter-like messages to a network port (generally sent using netcat) and directs them to a user or channel.
Private Messages with cometD Chat. cometd-java (a Java servlet reference implementation of the Bayeux protocol) can be extended with BayeuxService subclasses that run within the server itself.
Cascading. A Java API abstraction layer over Hadoop that lets developers think in terms of pipes and filters rather than map/reduce. The Cascading developers claim that this model is easier to understand and less error prone.
Keyczar (via) New open source cryptography toolkit from Google, designed to get algorithm selection, key rotation and versioning right so you don’t have to. Java and Python versions are available; the Python version depends on PyCrypto.
Protocol Buffers: Google’s Data Interchange Format. Open sourced today. Highly efficient binary protocol for storing and transmitting structured data between C++, Java and Python. Uses a .proto file describing the data structure which is compiled to classes in those languages for serializing and deserializing. 3-10 times smaller and 20-100 times faster than XML.
3 and 1/2 minutes to sort a Terabyte, and a look at Hadoop’s code structure. Bill de hÓra uses some clever static analysis tools to explore Hadoop’s 100,000+ lines of code.
Spicing Up Embedded JavaScript. John Resig collects the various ways in which a JavaScript interpreter can be hosted by Python, PHP, Perl, Ruby and Java. There are full JS implementations in PHP, Perl and Java; Ruby and Python both have modules that use an embedded SpiderMonkey.