Java Dependency Management with Ivy Part I

Java Dependency Management with Ivy Part I – The Basics

Along with the rich enterprise libraries that come as part of the language, one of the biggest advantages of Java is the vast number of third party libraries available. For example if you are writing an enterprise web application, GWT, Spring and Hibernate provide a framework with a huge amount of pre-existing functionality.

The size and number of dependencies grows as your application grows. GWT and Spring alone, without their dependencies, are more than 7MB. The ideal place to put dependencies is in a source control repository as part of your project so that when you or your continuous integration server check out the project for the first time all the dependencies are there. Then you don't have to go and get them and store them locally in a location that is agreed by the entire development team.

Storing the dependencies for a single project in a source control repository isn't too bad, provided there is plenty of room on the source control server.. However, if you have more than one project using the same or similar sets of dependencies the amount of space taken up in the source control repository starts to get a bit ridiculous. And then when a new version of a library comes out and you upgrade, even more space is wasted as the differences between binary jars cannot be detected, so the entire jar must be replaced.

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Write Your Own Load Balancer: A worked Example

I was out walking with a techie friend of mine I’d not seen for a while and he asked me if I’d written anything recently. I hadn’t, other than an article on data sharing a few months before and I realised I was missing it. Well, not the writing itself, but the end result. In the last few weeks, another friend of mine, John Cricket , has been setting weekly code challenges via linkedin and his new website, https://codingchallenges.fyi/ . They were all quite interesting, but one in particular on writing load balancers appealed, so I thought I’d kill two birds with one stone and write up a worked example. You’ll find my worked example below. The challenge itself is italics and voice is that of John Crickets. The Coding Challenge https://codingchallenges.fyi/challenges/challenge-load-balancer/ Write Your Own Load Balancer This challenge is to build your own application layer load balancer. A load balancer sits in front of a group of servers and routes client requests across all of the serv...

Catalina-Ant for Tomcat 7

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RESTful Behaviour Guide

I’ve used a lot of existing Representational State Transfer (REST) APIs and have created several of my own. I see a lot of inconsistency, not just between REST APIs but often within a single REST API. I think most developers understand, at a high level, what a REST API is for and how it should work, but lack a detailed understanding. I think the first thing they forget to consider is that REST APIs allow you to identify and manipulate resources on the web. Here I want to look briefly at what a REST API is and offer some advice on how to structure one, how it should behave and what should be considered when building it. I know this isn’t emacs vs vi, but it can be quite contentious. So, as Barbossa from Pirates of the Caribbean said, this “...is more what you’d call ‘guidelines’ than actual rules.” Resources & Identifiers In their book, Rest in Practice - Hypermedia and Systems Architecture (‎ISBN: 978-0596805821), Jim Webber, Savas Parastatidis and Ian Robinson describe resour...

Paul Grenyer

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