I encountered a subtle hibernate mapping issue involving Dates and Timestamps. The following test recreates this issue.
» Read more: Hibernate Date vs Timestamp
Archive for the ‘Java’ category
Hibernate Logging
January 30th, 2012Through the years I’ve encountered a recurring requirement. Clients need to log changes to the database for auditing and legal purposes. To satisfy this requirement you could add logging to every save/update/delete call in your code. Or better yet, you could create an aspect that wraps these calls. While these would certainly work Hibernate provides a convenient interceptor.
In this article I will show you how to add a simple logger to Hibernate.
» Read more: Hibernate Logging
Debugging memory leaks with VisualVM
July 18th, 2011At work I had run into a memory leak when scrolling through large result sets returned from Hibernate. I thought I had fixed it by performing a evict()/clear()/flush() in the HibernateTemplate that I was using but suddenly the leak was back. I was using VisualVm to monitor the heap so I started poking around to see if there was anything to help diagnose where the leak was.
» Read more: Debugging memory leaks with VisualVM
Maven 3 Tutorial – Project Setup
June 11th, 2011- Overview
- What is Maven?
- Plugins
- Why not Ant and Ivy?
- But It Downloads the Internet
- Getting Started
- Install
- What is a POM?
- Convention over Configuration
- New Project
- Project Management
- Parent POM
- Local Maven Repository
- Multiple Artifacts from a Single Source
- Release Plugin
- Aggregate POM
- Dependency Management
- Distribution Zip
- Conclusions
Overview
What is Maven?
Maven is a software project management and comprehension tool that includes: build tools, dependency management, project reporting and much more. I say “much more” because at the core Maven is a plugin execution framework. There are plugins supported by the Maven project (http://maven.apache.org/plugins/index.html), plugins supported by Mojo Project (http://mojo.codehaus.org/plugins.html), and third party plugins. If you can find or write a plugin, Maven can run it.
» Read more: Maven 3 Tutorial – Project Setup
Testing Spring Wiring
June 1st, 2011Overview
Spring is an essential part of my technology stack. I cann’t image providing quality software that doesn’t leverage an IoC container. However, decoupling components requires some amount of configuration. Whether this is accomplished through annotations or XML, it’s fairly easy to mess up. Fixing these missing or incorrect configurations doesn’t take very long. The real question is how quickly can you identify these errors?
This question of how long, is a feedback loop question. Unfortunately many teams wait until they fire up the application server to see if their Spring context is wired correctly. This is too late.
One of our clients suffered from this very issue. Due to environmental constraints they could not run automated, in-container tests that would have identified misconfigured beans. After repeatedly committing stupid configuration mistakes, I decided that I would write a Spring wiring test. As I began to write this I encountered five problems.
» Read more: Testing Spring Wiring
Mock Me With Fewer Words
May 1st, 2011With Mockito 1.8.3 or higher you can significantly reduce your test code setup.
» Read more: Mock Me With Fewer Words
Rethinking the DAO-Service layer relationship
April 8th, 2011Lately I have been thinking that the standard service-calling-the-dao-layer architecture hasn’t been working out as well as I would hope. The applications I have been working on have been using Spring and Hibernate with a dao object per model object. While this does provide a good separation between the two, I have been finding it increasingly difficult to write good tests for the service layer as the project matures. Past experience has shown that if writing tests is difficult, then it just isn’t done. Follow along as I think about possible ways to address this issue.
» Read more: Rethinking the DAO-Service layer relationship
Selenium IDE – Part II
April 1st, 2011In Part I we covered
- Setting Up
- Recording Tests
- Playing Back Tests
- Saving Test Cases
- Resuming Recording
- Saving Test Suites
All examples will use the sample site https://sites.google.com/site/example4selenium/.
Store Value
- There are two ways to store values.
- First, you can define custom variables
- Second you can use the drop-down ’storeText’ option.
Would you start mocking me?
August 5th, 2010One of the primary principles of unit testing is to test a small piece of functionality in isolation. In order to achieve this, mock objects are often necessary. Historically using mocks could be quite painful. After using several mock frameworks, my favorite by far is Mockito.
Tutorial
In this tutorial we will walk through examples of the most common features of Mockito. My sample project can be downloaded here.
Interfaces and Implementation
Some mocking frameworks only supported mocking interfaces. As a result our projects became bloated with useless interfaces that were only used for testing. Mockito creates mock objects with interfaces or classes.
» Read more: Would you start mocking me?
MySQL Master/Slave configuration with EJB3 and JPA
March 26th, 2010Well this turned out to be quite an exercise.
The goal: scalable reads with MySQL in master-slave configuration, writing to the master, and reading from N slaves, load balanced in round-robin fashion (or something).
The problem: using JPA (Java Persistence API) instead of direct JDBC calls. Turns out the MySQL ReplicationDriver (used to load balance reads to slaves and send writes to the master) relies on the readOnly state of the Connection in order to decide whether it’s a read or a write. With direct JDBC calls, I could get the Connection and toggle the readOnly state as needed.
» Read more: MySQL Master/Slave configuration with EJB3 and JPA
