Eclipse JUnit – possible causes of seeing “initializationError” in Eclipse window

I know this question is pretty general but I haven’t found any hints on why this error may show up. What are possible causes of seeing initalizationError in Eclipse window? I get no useful information just a long and useless failure trace (not included here).

I am using JUnit 4.11

I have written the following code – just to see if it works:

package test;

import static org.junit.Assert.*;

import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class SimpleTest {

@BeforeClass
public static void setUpBeforeClass() throws Exception {
}

@AfterClass
public static void tearDownAfterClass() throws Exception {
}

@Test
public void test() {
    assertEquals(15, 15);
}

}

Edit: Sorry In Eclipse window it’s called actually a “Failure trace”:

java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing     at
java.lang.ClassLoader.defineClass1(Native Method)   at
java.lang.ClassLoader.defineClass(Unknown Source)   at
java.security.SecureClassLoader.defineClass(Unknown Source)     at
java.net.URLClassLoader.defineClass(Unknown Source)     at
java.net.URLClassLoader.access$100(Unknown Source)  at
java.net.URLClassLoader$1.run(Unknown Source)   at
java.net.URLClassLoader$1.run(Unknown Source)   at
java.security.AccessController.doPrivileged(Native Method)  at
java.net.URLClassLoader.findClass(Unknown Source)   at
java.lang.ClassLoader.loadClass(Unknown Source)     at
sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)  at
java.lang.ClassLoader.loadClass(Unknown Source)     at
org.junit.internal.builders.JUnit4Builder.runnerForClass(JUnit4Builder.java:10)
    at
org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at 
org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at
org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at
org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:26)
    at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.<init>(JUnit4TestReference.java:33)
    at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestClassReference.<init>(JUnit4TestClassReference.java:25)
    at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:48)
    at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:38)
    at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:452)
    at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.ClassNotFoundException:
org.hamcrest.SelfDescribing     at java.net.URLClassLoader$1.run(Unknown
Source)     at java.net.URLClassLoader$1.run(Unknown Source)    at
java.security.AccessController.doPrivileged(Native Method)  at
java.net.URLClassLoader.findClass(Unknown Source)   at
java.lang.ClassLoader.loadClass(Unknown Source)     at
sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)  at
java.lang.ClassLoader.loadClass(Unknown Source)     ... 25 more

Answer

You’ve probably got one of two problems:

1) You’re using JUnit 4.11, which doesn’t include hamcrest. Add the hamcrest 1.3 library to your classpath.

2) You’ve got hamcrest 1.3 on your classpath, but you’ve got another version of either junit or hamcrest on your classpath.

For background, junit pre 4.11 included a cut down version of hamcrest 1.1. 4.11 removed these classes.