IntelliJ java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing

Question

Yes before you close this thread I have read all the same question threads saying I need to add hamcrest to classpath. I don't understand what that means or how to do it. I have JDK 14 and don't know why I'm having random problems now. I just want to do JUnit testing.

"C:\Program Files\Java\jdk-14.0.1\bin\java.exe" -ea -Didea.test.cyclic.buffer.size=1048576 "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.1.1\lib\idea_rt.jar=50007:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.1.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.1.1\lib\idea_rt.jar;C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.1.1\plugins\junit\lib\junit5-rt.jar;C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.1.1\plugins\junit\lib\junit-rt.jar;C:\Users\amanu\Documents\hackerman\cmsc420summer20\pqueue\bin;C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.1.1\lib\junit-4.12.jar;C:\Users\amanu\.m2\repository\org\junit\jupiter\junit-jupiter\5.4.2\junit-jupiter-5.4.2.jar;C:\Users\amanu\.m2\repository\org\junit\jupiter\junit-jupiter-api\5.4.2\junit-jupiter-api-5.4.2.jar;C:\Users\amanu\.m2\repository\org\apiguardian\apiguardian-api\1.0.0\apiguardian-api-1.0.0.jar;C:\Users\amanu\.m2\repository\org\opentest4j\opentest4j\1.1.1\opentest4j-1.1.1.jar;C:\Users\amanu\.m2\repository\org\junit\platform\junit-platform-commons\1.4.2\junit-platform-commons-1.4.2.jar;C:\Users\amanu\.m2\repository\org\junit\jupiter\junit-jupiter-params\5.4.2\junit-jupiter-params-5.4.2.jar;C:\Users\amanu\.m2\repository\org\junit\jupiter\junit-jupiter-engine\5.4.2\junit-jupiter-engine-5.4.2.jar;C:\Users\amanu\.m2\repository\org\junit\platform\junit-platform-engine\1.4.2\junit-platform-engine-1.4.2.jar" com.intellij.rt.junit.JUnitStarter -ideVersion5 -junit4 pqueue.StudentTests

java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing

    at java.base/java.lang.ClassLoader.defineClass1(Native Method)
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:821)
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:719)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:642)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:600)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    at org.junit.internal.builders.JUnit4Builder.runnerForClass(JUnit4Builder.java:10)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:49)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.ClassNotFoundException: org.hamcrest.SelfDescribing
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    ... 18 more


Process finished with exit code -1

Edit

My confusion was IntelliJ asking me to add the path of the hamcrest-core-1.3.jar file. hamcrest-core-1.3.jar is already within the Java JDK installation. I thought this meant that hamcrest was already being used in the project, and that was the incorrect assumption.

Solution

I went to Project Structure -> Dependencies -> Looked for hamcrest within the JDK installation -> Added hamcrest-core-1.3.jar.

Answer 1

Try out following jar hamcrest-2.2.jar - https://search.maven.org/search?q=g:org.hamcrest

Answer 2

See this document describing which testing libraries are needed. And another document describing how you can add them to the module dependencies.

Basically you locate the jars or download them, then go to the Project Structure | Modules | Dependecies tab, click the + button and specify the path to the jar file(s).

If you decide to use Maven or Gradle, testing dependencies are easier to add in the build files and all the transitive dependencies will be downloaded and configured automatically.