Spring Boot and Liquidbase : how to change the default path and filename

Posted on 22nd July 2018 by Sylvain Leroy

This article is a hint how to change the default path and name for the liquibase changeset when you are using Spring Boot.

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1

Using S3 libraries with Minio mock server

Posted on 17th February 2018 by Sylvain Leroy

In the continuation of my previous S3 article,

I present you, how to write a S3 Java Sample program that is using a mock S3 server to develop the functionalities.

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3

Java developer testing toolbox

Posted on 31st January 2018 by Sylvain Leroy

An article dealing with Java application and testing frameworks and related libraries. Continue Reading →

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Quest for a CMS in 2018 : KeystoneJS Feedback

Posted on 30th January 2018 by Sylvain Leroy

I have received several requests after my first article dealing with CMS, Headless CMS (KeyStoneJS) and the rather gloomy conclusion.

This article is giving a feedback of my next experiences.

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2

How to implement CQRS with Spring : new framework

Posted on 24th December 2017 by Sylvain Leroy

This article is a presentation of a new little framework, I have developed and used on several projects.

The framework is for Spring Framework and requires Java 8.0. The code is on GitHub and downloadable from Bintray or JCenter.

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Test and Data Generation for Java Unit tests

Posted on 23rd December 2017 by Sylvain Leroy

Today I was preparing a presentation about Software Code quality for a TechTalk on Thursday. I made a search on Internet about Automatic Unit test generator and Data Generators. I will present some tools I have tried. Today, we will speak of Randoop.

Randoom Test Generator

The first tool name is Randoop.. This tool is existing since 2007 and its purpose is to generate automatically unit tests 🙂 Directly from your class definition!

To use it you have two choices:

You can use your software JAR or classpath directory.
You can include it in your test compile path (on gradle or maven) and creates a main or unit test.

To explain short the theory, thanks to the Java reflection it’s quite easy to produce automatic tests validating some contracts of your API.

Some examples: – toString() should never returns null or throws an Exception – equals() and compareTo() methods have a long list of constraints – Reflexivity: o.equals(o) == true – Symmetry: o1.equals(o2) == o2.equals(o1) – Transitivity: o1.equals(o2) && o2.equals(o3) ⇒ o1.equals(o3) – Equals to null: o.equals(null) == false – It does not throw an exception

Therefore this tool is generating unit tests with JUnit(TestSuite) for the list of classes you provide.

I have done some tests and you can reach 50-60% of coverage quite easily.

The main drawbacks of the solution are: – The unit tests are drawing a snapshot (precise picture) of your code and its behaviour however some tests are really non-sense and you don’t want to edit them. – They don’t replace handwritten tests since the tool is not understand the different between a String parameter emailand fullName. He will mostly use dumb strings.

About the technology, it’s not production ready: – I had troubles with the jar and its dependency plume. – The JAR is a fatjar and coming with dependencies that broke my software.

In conclusion, I will fork the software and try to fix the problems to make it more popular 🙂

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My weekly DZone”s digest #1

Posted on 23rd December 2017 by Sylvain Leroy

This is my first post that offers a digest from a selection of DZone’s articles. I will pick DZone’s article based on my interests.

This week the subjects are : BDD Testing, Bad code, Database Connection Pooling, Kotlin, Enterprise Architecture

A few benefits you get by doing BDD

A few benefits you get by doing BDD : This article is an introduction to the Behaviour Driven Development practice. It’s interesting because we are regularly meeting teams, developers, architectures (pick your favorite one) that are confusing technical details and functionalities. As a result, the design, the tests and the architecture hides the user behaviour (the use cases ?) under a pile of technical stones. This article is a nice introduction. I recommend to go further these articles : * Your boss won’t appreciate tdd, try BDD * BDD Programming Frameworks * Java Framework JBehave.

Gumption Traps: Bad Code

Bad code, how my code…

Gumption Traps: Bad Code : an article about the bad code and how to deal with it.

{% blockquote Grzegorz Ziemoński%} The first step to avoid the bad code trap is to stop producing such code yourself. When faced with existing bad code,one must work smart to maintain motivation. {% endblockquote %}

This is a good introduction sentence. This week, I had a meeting with a skilled and amazing team. The meeting’s goal was to find a way to find the technical debt. The very technical debt that is ruining the application and undermining the team’s motivation. What I found interesting and refreshing in this article, is the pragmatic tone and the advice.

{% blockquote Grzegorz Ziemoński%} To avoid bad code, try to minimize the amount of newly produced bad code. {% endblockquote %}

How to avoid the depress linked to the bad code ? First of all, I want to say that developers are not receiving enough training on how to improve the code. Usually university / college courses are dedicated about How to use a framework. Therefore, few of them are able to qualify what is a bad code, what are its characteristics and de facto the ways to improve it. To avoid bad code, I try to demonstrate the personal benefits for the developers to improve their skills. Quality is not only a question of money (how much the customer is paying) but rather how much your company is paying attention to your training and personal development.

A lot of developers are overwhelmed under the technical debts without the appropriate tools (mind, technics, theory) to handle it. I try to give them gumptions about the benefits to be a better developer and how to handle the weakness of a sick application. To save a software rather than practicing euthanasia 🙂

Database Connection Pooling in Java With HikariCP

When we are discussing about Database connection pooling, most of my colleagues are relying on the good old Tomcat dbcp. However there is a niche, really funny and interesting, the guys that a competing for the best DBCP. And HikariCP is clearly a step ahead of everyone.

The article Database Connection Pooling in Java With HikariCP is presenting how to use a custom DBCP in your software.

Hikari Performance

I think it would have been great to present the differences with the standard DBCP and further debate on the advantages/disadvantages of the solutions. A good idea for a newt article 🙂

Concurrency: Java Futures and Kotlin Coroutines

Java Futures and Kotlin Coroutines An interesting article about how Java Futures and Kotlin co-routines can coexists. Honestly I am a little bit disappointed and thought that Kotlin would make things easier like in Node.JS

Are Code Rules Meant to Be Broken?

Another article about Code Quality and we could be dubious whether exists an answer to that question : Are Code Rules Meant to Be Broken.

I won’t enter too much in the details, the author’s point of view seems to be Code Rules are good if they are respected. If they are broken, it implies that the Code rules need to evolve 🙂 What do you think about it ?

Java vs. Kotlin: First Impressions Using Kotlin for a Commercial Android Project

This article is interesting since it presents a feedback session on using Kotlin in a Android project.

The following big PLUS to use Kotlin are :

Null safety through nullable and non-nullable types, safe calls, and safe casts.
Extension functions.
Higher-order functions / lambda expressions.
Data classes.
Immutability.
Coroutines (added on Kotlin 1.1).
Type aliases (added on Kotlin 1.1).

Quality Code Is Loosely Coupled

This article is explaining one of the most dangerous side of coding : Coupling. Must to read article despite the lack of schemas.

Five Habits That Help Code Quality

This article is a great introduction on code assessment. These five habits are indeed things to track in your software code as a sign of decay and code sickness.

The habits are : – Write (Useful) Unit Tests – Keep Coupling to a Minimum – Be Mindful of the Principle of Least Astonishment – Minimize Cyclomatic Complexity – Get Names Right

10 Good Excuses for Not Reusing Enterprise Code

This article is really useful in the context of Digital Transformation to assess which softwares you should keep and throw.

Example of excuses : – I didn’t know that code existed. – I don’t know what that code does. – I don’t know how to use that code. – That code is not packaged in a reusable manner.

…

Test proven design

An interesting article and example on how to improve your own code using different skills. I really recommend to read this article and the next future ones : Test proven design.

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How migrate from JBoss 5 to 7

Posted on 23rd December 2017 by Sylvain Leroy

This article is part of my working notes on the subject of "How to migrate Web applications running on JBoss AS 5 to the version 7".

JBoss Application Server – Wildfly

I will go straight to the details though here is some lines about JBoss Server.

From Wikipedia : JBoss Application Server(Now called Wildfly) is an application server authored by JBoss, now developed by Red Hat. WildFly is written in Java, and implements the Java Platform, Enterprise Edition (Java EE) specification. It runs on multiple platforms.

On 20 November 2014, JBoss Application Server was renamed Wildfly.

The product history according Wikipedia is :

5.1 Release 23 May 2009
7.0[10] Release 12 July 2011
7.1 Release February 2012
10.1.0 Release August 2016[20]

The JBoss AS community project has been renamed to the WildFly community project wildfly.org

According this JBoss 5 to 7 in 11 steps, the benefits are :

Processing time decreased by 25% without any code change. Development speed increased in my opinion (it is really hard to measure it) by 50% and we are much more productive (faster server restarts). Memory footprint lowered from 1GB to 512MB. Finally automatic application redeployment finally works! However there is always a price to pay – the migration took us 4 weeks (2 sprints).

Thanks to the presentation from Roberto Cortez, we have a clear picture of the migration.

JBOSS 5 Architecture

JBOSS 7 Architecture

The checklist

Prepare the checklist

When the PAAS or the Web application server have to be upgraded, several regressions may happen. The team has to pay attention to :

Server functionalities and integration : Performance, Security, Logging, Monitoring
Server configuration
Server deployment configuration
Application deployment configuration
Server API regressions
Application regressions
Training and risk management

Server functionalities and integration : between the versions, some functionalities and integrations provided by the server may have evolved, be fixed or simply disappeared.

Server configuration : The way the server has been configured, using scripts, GUI, may have changed, forcing the team to change their configuration files and finding the corresponding new way of doing it.

Server deployment configuration : Your deployment model configuration may have to be upgraded : single node, clustered mode, disaster recovery, high availability, reverse-proxying may behave differently in the new versions.

Application deployment configuration : the way to deploy your web applications may have changed in the new versions (GUI mode to script mode…)

Server API Regressions : usually Web Application servers are implementing a specific JEE API version, Servlet API and so on. These API may have changed causing regressions in your applications.

Application regressions : JBoss is including many components extending the JEE with BPM, Persistence, implementation. It is really important to track your dependencies (using Tattletale or mvn dependencies:tree) and interview your team about possible hacks and fixes to overcome the limits of JEE 5. This kind of workaround is difficult to migrate.

Training and risk management : This kind of migration contains its part of risks and changes. Both can create frictions inside your team of between the IT Team and your Dev teams. To ease the migration, don’t forget to dedicate some time to your teams into training to learn the new features of JAS 7. You will also have to adapt your project management to freeze for a while the features until the migration has been done.

Global checklist

This section is providing a checklist to help developers and managers to evaluate the migration risk of their applications.

Common issues

Here is a list of common issues during the migration of applications with JBOSS AS.

4.2. Debug Migration Issues 4.2.1. Debug and Resolve Migration Issues 4.2.2. Debug and Resolve ClassNotFoundExceptions and NoClassDefFoundErrors 4.2.3. Find the JBoss Module Dependency 4.2.4. Find the JAR in the Previous Install 4.2.5. Debug and Resolve ClassCastExceptions 4.2.6. Debug and Resolve DuplicateServiceExceptions 4.2.7. Debug and Resolve JBoss Seam Debug Page Errors

There is a deadlock when using EJB remoting over SSL. This deadlock is present even in EAP 6.2. We’re now at the point when we have quite a patch set of features backported from WildFly to AS 7.
JMS : JBoss Messaging server has been deprecated and the compatibility with a JBOSS AS 5 server is really tough to maintain. Some solutions exists as explained below in the article.

What is changing ?

Here is a summary of the evolutions between the JBoss AS version 5 and the version 6.

JBOSS AS 6 changes

Here is the compiled list of modifications including the minor version fixes.

[Server functionality, Server API, Application regressions] Module based class loading

In JBoss Enterprise Application Platform 5, the class loading architecture was hierarchical. In JBoss Enterprise Application Platform 6, class loading is based on JBoss Modules. This offers true application isolation, hides server implementation classes, and only loads the classes your application needs. Class loading is concurrent for better performance. Applications written for JBoss Enterprise Application Platform 5 must be modified to specify module dependencies and in some cases, repackage archives.

[Server functionality, Server deployment configuration] Domain Management : In JBoss Enterprise Application Platform 6, the server can be run as a standalone server or in a managed domain.
[Application Deployment] Deployment Configuration : Standalone Servers and Managed Domains : Boss Enterprise Application Platform 5 used profile based deployment configuration. These profiles were located in the EAP_HOME/server/ directory. Applications often contained multiple configuration files for security, database, resource adapter, and other configurations. In JBoss Enterprise Application Platform 6, deployment configuration is done using one file. JBoss Enterprise Application Platform 5 configuration files must be migrated to the new single configuration file.
[Server functionality, Application deployment configuration] Ordering of deployments : Application Platform 5 applications that consist of multiple modules deployed as EARs and use legacy JNDI lookups instead of CDI injection or resource-ref entries may require configuration changes.
[Server functionality, Application deployment configuration] Directory Structure and Scripts : As previously mentioned, JBoss Enterprise Application Platform 6 no longer uses profile based deployment configuration, so there is no EAP_HOME/server/ directory.
[Server application, Application deployment configuration, Application regression JNDI Lookups JBoss Enterprise Application Platform 6 now uses standardized portable JNDI namespaces.
[Server functionality, Server configuration, Application configuration, Application code] : Changing logging dependencies
[Server API, Application configuration regressions] Resource adapter configuration : In previous versions of the application server, the resource adapter configuration was defined in a file with a suffix of *-ds.xml. In JBoss Enterprise Application Platform 6, a resource adapter is configured in the server configuration file.
[Server libraries] Technologies upgrade : JDK 6, JSF 2, Bean Validation (JSR-303), CDI, EJB 3 (1.1.13)
Include mod_cluster
Servlet API 3.0
Update CL to 2.0.8.GA
Update Deployers to 2.0.9.GA
Update Javassist to 3.11.0.GA
Update JBossWS to 3.2.1.GA
Update JBossXB to 2.0.2.Beta3
Update JGroups to 2.6.13
Update Kernel to 2.0.9.GA
Update MC-INT to 2.2.0.Alpha2
Update MDR to 2.0.2.GA
Update to Entity Manager 3.5 and JPA 2
Update to JBoss AOP 2.1.6.GA
Update VFS to 2.2.0.Alpha1
Upgrade apache-beanutils to 1.8.0
Upgrade ha-server-cache-jbc to 2.1.0.GA
Upgrade JBoss Cache to 3.2.1.GA
Upgrade jboss-common-core to 2.2.16.GA
Upgrade jboss-ha-server-cache-jbc to 2.0.1.GA
Upgrade JBoss JAXR to 2.0.1
Upgrade JBoss LogManager to 1.1.0.GA
Upgrade JBoss Security 2.0.4.SP2
Upgrade JBossXACML to 2.0.4
Upgrade JSF to 2.0.0-RC
Upgrade to Java Mail 1.4.2
Upgrade to JBossXACML 2.0.3.SP2
Upgrade XNIO Metadata to 1.0.1.GA
New library JBossWS-CXF
library update RestEasy
JBoss Messaging JMS & MDB replaced by Hornet MQ
New RMI Framework : Remote 3
VFS Library update
[Server functionalities] new server functionalities : Mod_cluster, JBoss Embedded AS
[Application deployment] The legacy pooled invoker has been removed. Applications using the pooled invoker should switch to the JBoss Remoting-based unified invoker, which has been the default detached invoker since 4.2.

JBOSS AS Release 7

Here is the compiled list of modifications including the minor version fixes.

[Server functionality, Application regressions] Security improvement

Unlike previous releases, with AS 7.1, remote access requires secure authentication by default. This includes both managment (native, jmx, etc) and various remote application protocols (ejb, jndi, jms, etc); Added SSL support for the Remoting interfaces.

[Application configuration deployment] Management API improvements : All configuration attributes are updatable via the CLI. Direct edits to the XML are not necessary.
[Server functionality] Various Administration Console Improvements and Management changes
[Server API] Remote Connectivity Added support for remote EJB, JNDI and JMX invocation over JBoss Remoting 3, IIOP, Remote JMS. Three modes for accessing remote EE components using JNDI (Client, Traditional Remote, and Delegated).
[Server deployment model] Clustering Enhancements : Standalone Servers and Managed Domains : Numerours fixes in HTTP Session Replication, Clustered Web SSO, EJB Stateful Session Bean Replication, EJB load-balancing and failove, JPA XPC propagation
[Server functionality] CLI Regressions jboss-admin.sh renamed to jboss-cli.sh, data-source add" "--pool-name" argument seems to have changed to "–name".
[Server libraries] Technologies upgrade :
EJB 3.1 Full – Adds a number of key features, including remote communication, asynchronous method invocation, timers, message-driven beans, and legacy compatibility with EJB 2.
CMP 2 – Provides a legacy persistence manager which predates JPA. This is benefical to legacy applications which make use of EJB 2.x Entity Beans.
JAX-WS 2.2 – Allows simplified usage of Web Services in the EE platform.
JAX-RPC 1.1 – Offers legacy support for older Java EE Web Services applications.
JAX-RS 1.1 – Supports the construction of RESTful Web Services using the Java EE platform.
JavaMail 1.4 – Allows Java EE applications to send and receive e-mail
JCA 1.6 – Provides a mechanism for third parties to provide support for custom data sources, as well as connection pooling and transaction management for database access.
JMS 1.1 – Adds advanced messaging support to EE applications.
IIOP – Supports interoperablility with other application servers and non-Java CORBA clients.
JSR-88 – Allows for managing deployments to a Java EE server in a portable fashion.
Update mod_cluster to 1.2.0.Final
IronJacamar 1.0.7.Final
Upgrade Infinispan to 5.1.0.CR3
Upgrade to JBossTS 4.16.1
Upgrade jboss-metadata to 7.0.0.Beta33
Upgrade JGroups to 3.0.3.Final
Upgrade JBoss Marshalling to 1.3.6.GA
Upgrade httpcore to 4.1.4
Upgrade to JBossWS 4.0.1.GA and Apache CXF 2.4.6
Update to classfilewriter 1.0.1
Upgrade to JSF 2.1.7
Upgrade PicketLink to 2.0.2.Final
Upgrade PicketBox to 4.0.7.Final
Upgrade commons-beanutils to 1.8.3
Upgrade Google Guava to 11.0.2
[Server functionalities] new server functionalities : Mod_cluster, JBoss Embedded AS
[Application deployment] The legacy pooled invoker has been removed. Applications using the pooled invoker should switch to the JBoss Remoting-based unified invoker, which has been the default detached invoker since 4.2.
[Server functionalities] new server functionalities : Mod_cluster, JBoss Embedded AS
[Application deployment] The legacy pooled invoker has been removed. Applications using the pooled invoker should switch to the JBoss Remoting-based unified invoker, which has been the default detached invoker since 4.2.

How to migrate : plan and tasks

JDBC configuration
Classpath references
Global Modules Reference
JMS migration :

According link, we thought it would be really hard to connect with JMS server based on JBoss 5. It turned out that you have 2 options and both work fine:

Start HornetQ server on your own instance and create a bridge to JBoss 5 instance
Uses a JMS Bridge to move the existing messages
Use Generic JMS adapter: https://github.com/jms-ra/generic-jms-ra

Application packaging and configuration

Repackaging Dependencies and fix the EAR Layout: link
Install and configure the JDBC Driver link
Update the Resource Adapter Configuration
Configure the datasource for Hibernate and JPA : If your application uses JPA and currently bundles the Hibernate JARs, you may want to use the Hibernate that is included with JBoss Enterprise Application Platform 6.

In WildFly 8, a resource adapter is configured in the server configuration file. If you are running in domain mode, the configuration file is the domain/configuration/domain.xml file. If you are running in standalone mode, you will configure the resource adapter in the standalone/configuration/standalone.xml file.

More details there How to migrate from AS5 or AS6 to Wildfly

Migration of the shell scripts, integration test scripts, deployment scripts.

Application code and configuration migration

Here is the list of tasks implying some rewriting inside your application code.

Migration JEE 5 to JEE 6
Upgrade to JPA 2.0
Update your SOAP Implementations using JBossWS-CXF
Upgrade Hibernate from 3 to 4
Replacing JBOSS Cache by Infinispan Cache
Configure JAX-RS / Resteasy changes
Fix Hibernate’s sequencer
Replace JBOSS AOP Interceptors : JBoss AOP was used by the EJB container. However, in AS 7, the EJB container uses a new mechanism. If your application uses JBoss AOP, you need modify your application code as follows.
Migrating JNDI : Migrating JNDI namespaces
Update the datasources : link
Rewriting of your RMI Code : oss 5 and 7 are totally different and this kind of communication will not work.
Using CDI instead of plain old Singletons

Tooling

Here is a list of useful tools to assist you in your migration.

IronJacamar : to update your datasource configuration
Tattletale : to find the application dependencies
Gilder : An application for migrating the configuration of JBoss AS 5-based servers to JBoss AS 7-based servers.
Tools and tooling to migrate to JBOSSS 6 : Link
Upgrades to newer versions of WildFly or JBoss EAP may be handled using the JBoss Windup migration tool. JBoss Windup migration tool

References:

https://www.youtube.com/watch?v=eelLC2kF9bU
JBoss 6 release
JBoss 5 to 7 in 11 steps
JBoss Release note 6
JBoss Enterprise Application Details
PDF Migration JBOSS
JBOSS 5-7
JBoss Server migrqtion tool
How do I migrate my application from AS5 or AS6 to AS7
JBOSS 5 to 7
Migration tales JEE 5 to 7

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How I switched my blog from OVH to Google Container Engine

Posted on 23rd December 2017 by Sylvain Leroy

In this short story, I will relate how I migrate my blog personal website from a classic VM instance to a container using Google Cloud Container Engine and Kubernetes, Docker, Nginx.

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