JMockit - initialization problem

Question

When I use the following test I get a WARNING:

WARNING: JMockit was initialized on demand, which may cause certain tests to fail; please check the d

Answer 1

I had no difficulties running my tests in Maven but I got the same error when I was running them in eclipse.

The JMockit Eclipse plugin allowed me to run all the test in eclipse without any extra configuration.

https://marketplace.eclipse.org/content/jmockit-eclipse

One of the featues of this plugin is

Automatically adds JMockit jar as -javaagent argument to JUnit launches.

Answer 2

The accepted answer has fallen a little out of date regarding the links so it's worth mentioning the various solutions directly.

To fix this problem do one of the following:

1 - Specifiy a javaagent

Add this to your JUnit execution environment (for your version):

 -javaagent:path/to/your/jmockit/jmockit-0.998.jar 

2 - configure the Surefire plugin in Maven to avoid it

Add the following to your Maven configuration (choose your own versions)

<!-- JMockit must be before JUnit in the classpath -->
<dependency>
  <groupId>mockit</groupId>
  <artifactId>jmockit</artifactId>
</dependency>
<!-- Standard unit testing -->
<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
</dependency>

Ensure that your Surefire plugin is configured as follows (for your particular versions):

<plugin>
   <groupId>org.apache.maven.plugins</groupId>
   <artifactId>maven-surefire-plugin</artifactId>
   <version>2.4.3</version>
   <configuration>
      <argLine>-javaagent:${settings.localRepository}/mockit/jmockit/0.998/jmockit-0.998.jar</argLine>
      <useSystemClassLoader>true</useSystemClassLoader>
    </configuration>
 </plugin>

3 - Use the JUnit @RunWith annotation

Add this JUnit runner annotation on each and every test class

@RunWith(JMockit.class)
public class ExampleTest {}

Answer 3

I setup a properties file in the classpath for easy configuration of Junit 5:

It MUST be named junit-platform.properties

junit.jupiter.extensions.autodetection.enabled = true
junit.jupiter.testinstance.lifecycle.default = per_class

Make sure you're using a newer version of Jmockit that has the JmockitExtension class. NOTE: Jmockit version 1.8 IS NOT newer than version 1.41. The 1.8 version should have been 1.08.

Maven Central reference: https://mvnrepository.com/artifact/org.jmockit/jmockit

Answer 4

It still doesnt run for me in IntelliJ. I am able to run it command line though.

Answer 5

As I understand it, this exception is thrown when one attempts to call a JMockit method, while JMockit has not been properly initialized.

Make sure you follow the JMockit installation instructions, especially points 3 and 4. If the JMockit jar comes after the JUnit jar in the classpath, it might cause problems.

Answer 6

I simply added:

@RunWith(JMockit.class)

Which resolved the issue, as per the documentation in the accepted answer.