Wildfly 10 - HSQL Datascource - null pointer excception testing connection to database - datasource

Question

I would like to know if anybody is aware of the following problem in wildfly 10.
When trying to setup a datasource for HSQL, I was confronted with the problem where for a non xa data source driver, you would expect the configuration element connection-url to be of any use. In particular, this configuration element is of use when you attempt to connect to H2 or oracle.
However, when testing the following configuration I was systematically hitting a null pointer exception on HSQL getConnection.
The hsql modulue is added as jboss module with:
<module xmlns="urn:jboss:module:1.3" name="org.hsql">
<properties>
</properties>
<resources>
<resource-root path="hsqldb-2.3.2.jar"/>
</resources>
<dependencies>
<module name="javax.api"/>
<module name="javax.transaction.api"/>
</dependencies>
</module>
The original configuration of the datasource, the one that does not work was as follows:
<datasource jta="false" jndi-name="java:/jdbc/HSQL_NON_JTA_DS" pool-name="HSQL_NON_JTA_DS" enabled="true" use-ccm="true">
<connection-url>jdbc:hsqldb:hsql://localhost:9001/DATABSE</connection-url>
<datasource-class>org.hsqldb.jdbc.JDBCDataSource</datasource-class>
<driver>hsql</driver>
<security>
<user-name>USER</user-name>
<password>USER</password>
</security>
</datasource>
<driver name="hsql" module="org.hsql">
<datasource-class>org.hsqldb.jdbc.JDBCDataSource</datasource-class>
</driver>
With the following stack trace:
2017-03-01 18:08:47,083 WARN [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (thread: management task-6) IJ000604: Throwable while attempting to get a new connection: null: javax.resource.ResourceException: IJ031084: Unable to create connection
at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createLocalManagedConnection(LocalManagedConnectionFactory.java:343)
at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.getLocalManagedConnection(LocalManagedConnectionFactory.java:350)
at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:285)
at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.createConnectionEventListener(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:1319)
at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.getConnection(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:496)
at org.jboss.jca.core.connectionmanager.pool.AbstractPool.internalTestConnection(AbstractPool.java:1061)
at org.jboss.jca.core.connectionmanager.pool.strategy.OnePool.testConnection(OnePool.java:93)
at org.jboss.as.connector.subsystems.common.pool.PoolOperations$TestConnectionInPool.invokeCommandOn(PoolOperations.java:234)
at org.jboss.as.connector.subsystems.common.pool.PoolOperations$1.execute(PoolOperations.java:90)
at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:890)
at org.jboss.as.controller.AbstractOperationContext.processStages(AbstractOperationContext.java:659)
at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:370)
at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1344)
at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:392)
at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:217)
at org.jboss.as.domain.http.server.DomainApiHandler.handleRequest(DomainApiHandler.java:212)
at io.undertow.server.handlers.encoding.EncodingHandler.handleRequest(EncodingHandler.java:72)
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler$1.run(SubjectDoAsHandler.java:72)
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler$1.run(SubjectDoAsHandler.java:68)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:422)
at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:92)
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler.handleRequest(SubjectDoAsHandler.java:68)
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler.handleRequest(SubjectDoAsHandler.java:63)
at io.undertow.server.handlers.BlockingHandler.handleRequest(BlockingHandler.java:56)
at org.jboss.as.domain.http.server.DomainApiCheckHandler.handleRequest(DomainApiCheckHandler.java:95)
at io.undertow.security.handlers.AuthenticationCallHandler.handleRequest(AuthenticationCallHandler.java:52)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at org.hsqldb.jdbc.JDBCDataSource.getConnection(Unknown Source)
at org.hsqldb.jdbc.JDBCDataSource.getConnection(Unknown Source)
at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createLocalManagedConnection(LocalManagedConnectionFactory.java:312)
... 31 more
This null pointer exception happend, quite simply because.
In the JDBCDataSource.java of HSQL, the following method was getting a null URL.
Meaning, JBOSS had not picked up the URL on the connection-url and configured on the driver.
private Connection getConnection(String url,
Properties props) throws SQLException {
if (!url.startsWith("jdbc:hsqldb:")) {
url = "jdbc:hsqldb:" + url;
}
return JDBCDriver.getConnection(url, props);
}
NOTE: If you want to debug HSQL you need to use the -debug.jar files that HSQL releases internally.
In any case...
After finding out that the subsytem for data sources is provided by IRON JCAMAR, it was possible to hunt the documentation for extra configuration properties to work-around what should never have been a problem.
Here is the documentation on elements supported for the data-source.
http://www.ironjacamar.org/doc/userguide/1.1/en-US/html_single/index.html#deployingds_descriptor
Ultiamtely, to make the connection work It was necessar to enrich it with the following element.
<connection-property name="url">jdbc:hsqldb:hsql://localhost:9001/DATABSE</connection-property>
Does it make any sense that additional element was necessary? It should have been redundant and unecessary. It is a good thing that custome data source properties are to be supported.
In this case, Is the problem with HSQL or is the problem with JBOSS.
In eery other app server, specifying the connection URL has always worked fine.
To me this appars to be a particular behavior of Wildfly.
This quite a problem since your average documentation on data sources just makes it abundantly clear that the connection-url is the element you do need to configure. In this case, it really is not.
Many thanks for a reply on this.

Answer 1

Looks like configuration issue. Update module name to org.hsqldb in datasource and module.xml file to follow standard module naming conventions. Update directory name from hsql to hsqldb under modules directory. It's all up to you. You can use your custom module naming convention too.
Some of the drivers does not have getURL() method implemented in their datasource classes. So, we have to specify datasource configuration differently for them.
Like Postgres, does not have getURL method. So, we will specify properties like this in our stanalone.xml/domain.xml file.
<xa-datasource-property name="ServerName">DatabaseHostName</xa-datasource-property>
<xa-datasource-property name="PortNumber">DatabasePortName</xa-datasource-property>
<xa-datasource-property name="DatabaseName">DatabaseName</xa-datasource-property>
<xa-datasource-class>com.edb.xa.PGXADataSource</xa-datasource-class>
<driver>postgresql</driver>
<security>
<user-name>database.username</user-name>
<password>database.password</password>
</security>
Whereas in case of Oracle which has getURL method implemented, configuration given below works fine.
<xa-datasource-property name="URL">jdbc:oracle:thin:#database.host:database.port:database.name</xa-datasource-property>
<xa-datasource-class>oracle.jdbc.xa.client.OracleXADataSource</xa-datasource-class>
<driver>oracle</driver>
I am not sure about HSQL driver implementation of getURL API. You can try specifying properties like I mentioned for Postgres and check if it works for your use-case.