Here we collect some common issues encountered by students during lab sessions that can be very hard to troubleshoot and resolve.

This page will be continuously expanded as the course progresses. If you have some suggestions to problems that you think should be included here, please leave us a message with your recommendation in the F.A.Q (Common Issues) recommendations topic on the discussion board.

Question / Answer

Q: When we try to create a database in Derby and the database explorer in NetBeans, we get one or more of the following error(s):

An error occurred while creating the database:
java.sql.NonTransientConnectionException: DERBY SQL error: ERRORCODE:
40000, SQLSTATE: XJ041, SQLERRMC: ...

Caused by: java.security.AccessControlException: access denied
("java.lang.RuntimePermission" "getenv.SOURCE_DATE_EPOCH")

A: This is some kind of missconfiguration in the JVM with a very aggressive security policy that doesn't allow applications to fetch the time on the system (since epoch). The solution is to edit `~/.java.policy` or `[java.home]/lib/security/java.policy` and add the following:

grant {
    permission java.lang.RuntimePermission "getenv.SOURCE_DATE_EPOCH", "read";
};

If you are on Windows you can read about where this policy file is supposed to be located here;
https://docs.oracle.com/javase/7/docs/technotes/guides/security/PolicyFiles.html

Q: When we try to run our tests from within NetBeans, the execution fails and we get one or more of the following exception(s):

org.jboss.arquillian.container.spi.client.container.LifecycleException: Could not start GlassFish Embedded
	at fish.payara.arquillian.container.payara.embedded.PayaraContainer.start(PayaraContainer.java:200)
	at org.jboss.arquillian.container.impl.ContainerImpl.start(ContainerImpl.java:179)

java.net.BindException: Adress already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:433)
	at sun.nio.ch.Net.bind(Net.java:425)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)

After this, the tests don't run and the application is not deployed.

A: After Payara version 5.181, the dependency on HazelCast changed to a more recent version. HazelCast is what Payara uses to handle it's clustering handling and clustering logic of Payara Servers and their internal data. It seems that the behavior of how ports are allocated has changed slightly. The error occurs because the "normal" instance of Payara started by NetBeans clashes with Payara Embedded.

To solve this problem you can stop the instance of Payara started by NetBeans. You can stop the instance by right clicking on "Servers > Payara Server" in the "Services" tab and choosing "Stop". However, this is not really practical during development and will force you to keep restarting your Payara instance.

Instead, you can go into your pom.xml and change the payara-embedded-all dependency to version 5.181 that uses an older version of HazelCast with the old (less broken) behavior:

<dependency>
        <groupId>fish.payara.extras</groupId>
        <artifactId>payara-embedded-all</artifactId>
        <version>5.181</version>
        <scope>test</scope>
</dependency>

This error can also be caused by some other external application actually occupying one of the ports that the embedded server is trying to bind to - in which case you should disable that application. AnyDesk for example uses the same port (7070) as the embedded Payara server starts on.

Q: When "src/main/setup/glassfish-resources.xml" is placed in our project tree structure, the deployment of the application takes a very long time (on some computers it can take several minutes). Sometimes it even seems to completely freeze - forcing us to restart NetBeans to get everything working again.

A: This issue is caused by a bug in NetBeans trying to access a non-existent schema as defined inside the glassfish-resources.xml file. You can read about this bug here https://github.com/payara/Payara/issues/4477.

This issue is easily fixed by editing your glassfish-resources.xml file and changing the schema of the file to the following:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE resources PUBLIC "-//Payara.fish//DTD Payara Server 5 Resource Definitions//EN" "https://raw.githubusercontent.com/payara/Payara-Server-Documentation/master/schemas/payara-resources_1_6.dtd">

After this, the deployment should be a lot faster and the resource should be created inside the application server.

Q: When trying to run the test suite, all the tests seem to be failing with no apparent reason being reported. Arquillian returns a null exception and there is no relevant information in the debug log of the tests. Even after looking through all the exceptions of the log there doesnt seem to be anything to "go on".

A: This one can be very confusing. What is happening is that Arquillian is simply refusing to start because it's unable to initialize the Payara Embedded server. Payara simply fails to start and doesn't report anything useful back to Arquillian.

The cause of this issue is an incompatibility with the JVM version that you are running the tests on. When you run the embedded Payara container, it will run that container within the JVM of the tests. Payara only supports the stable LTS (long term support) releases of Java. The other releases in-between are considered test releases to try out new features of the language and move development forward quicker.

The solution is to make sure that you run your tests under Java 8 or Java 11 (these are the two most recent LTS versions).

To change the Java version of the project, right click on the project in the Project tab and select Properties. Then change the Java version in the following location of the Project Properties:

2020-02-20 07-24-18.png

Depending on the Java versions you have installed, you may have to "Manage Java Platforms" and manually add either Java 8 or Java 11 to the list of supported Java platforms.

Q: How do you get NetBeans to skip the tests on request when building and deploying the project?

A: There are a number of ways to do this. One of the easier ones is to just add a skip-tests configuration profile that changes the default behavior when the project is built. You can do this under the project properties by right clicking on the project view in NetBeans:

2020-02-26 09-13-41.png

You then define the action under this profile and specify that the Build rule should skip the tests:

2020-02-26 09-13-57.png

Once defined, you can switch between the profiles by right clicking on the project in the project tab.