Home » Author Archives: Geoffrey De Smet

Author Archives: Geoffrey De Smet

Geoffrey De Smet (Red Hat) is the lead and founder of OptaPlanner. Before joining Red Hat in 2010, he was formerly employed as a Java consultant, an A.I. researcher and an enterprise application project lead. He has contributed to many open source projects (such as drools, jbpm, pressgang, spring-richclient, several maven plugins, weld, arquillian, ...). Since he started OptaPlanner in 2006, he’s been passionately addicted to planning optimization.

What is the fastest Garbage Collector in Java 8?

java-logo

OpenJDK 8 has several Garbage Collector algorithms, such as Parallel GC, CMS and G1. Which one is the fastest? What will happen if the default GC changes from Parallel GC in Java 8 to G1 in Java 9 (as currently proposed)? Let’s benchmark it. Benchmark methodology Run the same code 6 times with a different VM argument (-XX:+UseSerialGC, -XX:+UseParallelGC, -XX:+UseConcMarkSweepGC, ...

Read More »

OptaPlanner – How fast is logging?

software-development-2-logo

What’s the cost of trace/debug logging in production? What’s the performance cost of logging to a file? In these benchmarks, I compare the performance impact of logging levels (error, warn, info, debug, trace) and logging appenders (console appender, file appender) on several realistic OptaPlanner use cases. Benchmark methodology Logging implementation: SFL4J 1.7.2 with Logback 1.0.9 (Logback is the spiritual successor ...

Read More »

Drools 6.2.0.Final Released

jboss-drools-logo

We are happy to announce the latest and greatest Drools 6.2.0.Final release. This release in particular had a greater focus on improved usability and features that make the project easier to use (and adopt). Lots of improvements on the workbench UI, support for social activities and plugin management, as well as a brand new Execution Server for rules are among ...

Read More »

OptaPlanner – Scaling Vehicle Routing with Nearby Selection

optaplanner-logo

OptaPlanner 6.2 has made big step forward for the Vehicle Routing Problem (VRP), Traveling Salesman Problem (TSP) and similar use cases. The new feature nearby selection enables it to scale to bigger problems much more efficiently without sacrificing potential optimal solutions (which is common for inferior techniques). Let’s take a closer look at nearby selection with the Vehicle Routing Problem. ...

Read More »

Red Hat JBoss BRMS and BPMS Rich Client Framework demonstrating Polyglot Integration with GWT/Errai/UberFire and AngularJS

java-interview-questions-answers

Last week I published a blog highlighting a presentation I gave showing our rich client platform that has resulted from the work we have done within the BRMS and BPMS platforms, the productised versions of the Drools and jBPM projects. The presentation is all screenshots and videos, you can find the blog and the link to the slideshare here: “Red ...

Read More »

Prototyping an enterprise webapp at Devoxx Hackergarten

jboss-drools-logo

For the 10th year in a row, I attended DevoxxBe. It’s my favorite Java conference, but the talk schedule isn’t always optimal: sometimes I want to see 2 great talks at the same time! So at the Hackergarten at Devoxx, between attending talks, a few of us started building a webapp to improve the schedule. We’re calling the prototype OptaConf ...

Read More »

OptaPlanner – Open benchmarks for the win

software-development-2-logo

Recently, there was some commotion on Twitter because a competitor heavily restricts publicising benchmarks of their Solver as part of their license. That might seem harsh, but I can understand the sentiment: when a competitor publicizes a benchmark report comparing our product against their own, I know we’re gonna get screwed. Unlike single product benchmarking, competitive benchmarking is inherently dishonest…​ ...

Read More »

OptaPlanner – Vehicle routing with real road distances

optaplanner-logo

In the real world, vehicles in a Vehicle Routing Problem (VRP) have to follow the roads: they can’t travel in a straight line from customer to customer. Most VRP research papers and demo’s happily ignore this implementation detail. As did I, in the past. Although using road distances (instead of air distances) doesn’t impact the NP-hard nature of a VRP ...

Read More »

Cheating on the N Queens benchmark

software-development-2-logo

Many Solver distributions include an N Queens example, in which n queens need to be placed on a n*n sized chessboard, with no attack opportunities. So when you’re looking for the fastest Solver, it’s tempting to use the N Queens example as a benchmark to compare those solvers. That’s a tragic mistake, because the N Queens problem is solvable in ...

Read More »
Want to take your Java Skills to the next level?
Grab our programming books for FREE!
  • Save time by leveraging our field-tested solutions to common problems.
  • The books cover a wide range of topics, from JPA and JUnit, to JMeter and Android.
  • Each book comes as a standalone guide (with source code provided), so that you use it as reference.
Last Step ...

Where should we send the free eBooks?

Good Work!
To download the books, please verify your email address by following the instructions found on the email we just sent you.