Automatically reconnect to a database after a failure in JBoss EAP 7

My JBoss EAP 7 server couldn’t cope with a failing database. After a database restart or failure, e.g. due to maintenance, it simply would not connect to the database again automatically. The application simply stopped working as soon as the database was unavailable for a short period of time.

JBoss’s server.log was full of (not very helpful) error messages like this:

2017-03-01 12:05:18,175 ERROR [it.macke.repository.UserRepository] (default task-17) Error reading user: org.hibernate.exception.JDBCConnectionException: could not prepare statement: javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: could not prepare statement
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(
Caused by: org.hibernate.exception.JDBCConnectionException: could not prepare statement
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(
Caused by: java.sql.SQLNonTransientConnectionException: Connection is close
    at org.mariadb.jdbc.internal.util.ExceptionMapper.get(

To make the application work again, I had to restart JBoss and every now and then even the whole Windows server on which it runs.

As it turns out, this is a common problem with JBoss. However, the solution is quite easy. You only need to configure JBoss to validate the database connections. Here’s how this would look in standalone.xml (take a look at the content of element validation):

<datasource jndi-name="java:jboss/jdbc/MyDS" pool-name="MyDS">
        <check-valid-connection-sql>select 1</check-valid-connection-sql>
        <exception-sorter class-name="org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLExceptionSorter"/>

And if you want to script the setting, here’s the code for the CLI:

/subsystem=datasources/data-source=MyDS:write-attribute(name=check-valid-connection-sql,value="select 1")

The above settings make JBoss validate the connection on every new request (validate-on-match). But you can also have it do the checking in the background, e.g. every few seconds. And you need to consider the correct setting for your database. I use MariaDB/MySQL for my application and the exception-sorter and check-valid-connection-sql might be different depending on your database (e.g. and select 1 from dual for Oracle). Take a look at the available parameters here: Database Connection Validation JBoss EAP 7 – Configuration Guide

How to test JBoss EAP 7 with Arquillian

It took me quite some time to get my Arquillian tests running against a remote JBoss EAP 7.0.0.Beta1 application server, so I thought I’d share my configuration.

At the time of this writing, there was no Arquillian container adapter for JBoss EAP 7 available. So I had to use the Arquillian Chameleon Container. However, it turns out, that Chameleon is even easier to configure than a specific container, because it more or less configures itself. Chameleon automatically downloads the needed container for you, if you tell it what application server you want to use.

Java project

Arquillian dependencies

Let’s start with the dependencies in

// main BOM for Arquillian
// JUnit container
// Chameleon


My arquillian.xml looks like this.

<arquillian xmlns=""
    <container qualifier="chameleon" default="true">
            <property name="chameleonTarget">jboss eap:7.0.0.Beta:remote</property>
            <property name="managementAddress">THE_SERVERNAME_OR_IP</property>
            <property name="managementPort">THE_PORT_IF_NOT_9990</property>
            <property name="username">THE_USER</property>
            <property name="password">THE_PASSWORD</property>

The single line containing chameleonTarget defines the target server to be a remote JBoss EAP 7. That means, JBoss has to run on the target machine at the specified address or hostname and port. I chose this style of testing over the managed alternative, because it reduces the overhead of starting and stopping the server during tests. In addition, I think it’s a more realistic test, as the application gets deployed to a “real” server.

Arquillian test

I can now write a test against the server like this:

public static WebArchive createDeployment()
    return ShrinkWrap
        .addAsWebInfResource(EmptyAsset.INSTANCE, "beans.xml")
        .addAsResource("arquillian/persistence.xml", "META-INF/persistence.xml");

public void authenticateUser()
    // asserts


My persistence.xml for the Arquillian test simply uses JBoss’s default data source for the test. Hibernate creates and drops the tables before and after each test run.

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
    xmlns="" xmlns:xsi=""
    <persistence-unit name="myPU">
            <property name="" value="create-drop" />

Server configuration

To successfully run the test, quite some configuration on the server side was needed. Here’s what I had to do.

Add a management user

If you want to deploy to a remote JBoss server, you need a management user. If you test against a JBoss server on your local machine, this is not the case. The credentials have to be configured in arquillian.xml (see above).


What type of user do you wish to add?
 a) Management User (
 b) Application User (
(a): a

Enter the details of the new user to add.
Using realm 'ManagementRealm' as discovered from the existing property files.
Username : remote
Password recommendations are listed below. To modify these restrictions edit the configuration file.
 - The password should be different from the username
 - The password should not be one of the following restricted values {root, admin, administrator}
 - The password should contain at least 8 characters, 1 alphabetic character(s), 1 digit(s), 1 non-alphanumeric symbol(s)
Password :
WFLYDM0098: The password should be different from the username
Are you sure you want to use the password entered yes/no? yes
Re-enter Password :
What groups do you want this user to belong to? (Please enter a comma separated list, or leave blank for none)[  ]:
About to add user 'remote' for realm 'ManagementRealm'
Is this correct yes/no? yes
Added user 'remote' to file 'C:\jboss-eap-7.0.0.Beta\standalone\configuration\'
Added user 'remote' to file 'C:\jboss-eap-7.0.0.Beta\domain\configuration\'
Added user 'remote' with groups  to file 'C:\jboss-eap-7.0.0.Beta\standalone\configuration\'
Added user 'remote' with groups  to file 'C:\jboss-eap-7.0.0.Beta\domain\configuration\'
Is this new user going to be used for one AS process to connect to another AS process?
e.g. for a slave host controller connecting to the master or for a Remoting connection for server to server EJB calls.
yes/no? no

Bind to the public IP address

To make JBoss listen on the public IP address of the server, add this to \standalone\configuration\standalone.xml. The default configuration only allows connections on, which of course won’t be available from the outside.

    <interface name="management">
        <any-address />
    <interface name="public">
        <any-address />

Local repository

If you use a local repository like Artifactory (perhaps because you are behind a proxy server like me), you need to configure Maven to use this repository. Arquillian Chameleon downloads its needed artifacts directly during the test (and not during the build, where your individual repository would be configured in the build file) and uses whatever repository is configured as central. In my case, Chameleon could not connect to to download its dependencies, so I had to configure the local repository in the central Maven configuration file ~\.m2\settings.xml like so:

<settings xmlns=""