InitializationError When Use Spring Test + JUnit

The Problem
When we tried to use Spring Unit Testing framework with JUnit in our project, the simple test failed with error: "initializationError[Runner: JUnit 4]"

I imported the SpringJUnitIntro project to eclipse, it works.
But if I copied all classes to our project, it failed with initializationError. So this should be our project configuration issue.

Google Search, didn't find any thing quite useful.

Then I ran the test in debug mode, it stopped at 
Thread [main] (Class load: SpringJUnit4ClassRunner)
owns: Object  (id=24)
Class.getDeclaredConstructors0(boolean) line: not available [native method]
Class.privateGetDeclaredConstructors(boolean) line: 2671
Class.getConstructor0(Class[], int) line: 3075
Class.getConstructor(Class...) line: 1825
AnnotatedBuilder.buildRunner(Class, Class) line: 29
AnnotatedBuilder.runnerForClass(Class) line: 21
AnnotatedBuilder(RunnerBuilder).safeRunnerForClass(Class) line: 59 //\\
AllDefaultPossibilitiesBuilder.runnerForClass(Class) line: 26
AllDefaultPossibilitiesBuilder(RunnerBuilder).safeRunnerForClass(Class) line: 59
ClassRequest.getRunner() line: 26
FilterRequest.getRunner() line: 31
JUnit4TestLoader.createFilteredTest(Class, String, String[]) line: 77
JUnit4TestLoader.createTest(Class, String, String[], RemoteTestRunner) line: 68
JUnit4TestLoader.loadTests(Class[], String, String[], RemoteTestRunner) line: 43
RemoteTestRunner.runTests(String[], String, TestExecution) line: 444
RemoteTestRunner.runTests(TestExecution) line: 678
RemoteTestRunner.run() line: 382
RemoteTestRunner.main(String[]) line: 192

Then I use F7 to step return, an AnnotatedBuilder(RunnerBuilder).safeRunnerForClass(Class) line: 61, I found the root cause of the issue.

The Throwable e is java.lang.ExceptionInInitializerError,  run "e.printStackTrace();" in Eclipse Display view, then I found the root cause of the issue:
java.lang.ExceptionInInitializerError
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
  ...
Caused by: java.lang.IllegalStateException: SpringJUnit4ClassRunner requires JUnit 4.12 or higher.
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.(SpringJUnit4ClassRunner.java:102)
... 18 more

org.springframework.test.context.junit4.SpringJUnit4ClassRunner:

static {
  if (!ClassUtils.isPresent("org.junit.internal.Throwables", SpringJUnit4ClassRunner.class.getClassLoader())) {
    throw new IllegalStateException("SpringJUnit4ClassRunner requires JUnit 4.12 or higher.");
  }

  withRulesMethod = ReflectionUtils.findMethod(SpringJUnit4ClassRunner.class, "withRules",
      FrameworkMethod.class, Object.class, Statement.class);
  if (withRulesMethod == null) {
    throw new IllegalStateException("SpringJUnit4ClassRunner requires JUnit 4.12 or higher.");
  }
  ReflectionUtils.makeAccessible(withRulesMethod);
}

At org.junit.internal.runners.ErrorReportingRunner.describeCause(Throwable), the inner exception is lost

  private Description describeCause(Throwable child) {
      return Description.createTestDescription(fTestClass,
              "initializationError");
  }

After upgrade JUnit from 4.11 to 4.12, everything works fine.

Lesson Learned
Try run in debug mode
Use latest version of a library
Version conflict is a common issue in Java.
-- Use different versions of same library
-- Use lower version than supported: 
-- Check least version of X supported
Spring test framework requires JUnit 4.12 or higher. 
-- Check what version of X the library support
-- Check project readme
Example: spark-csv is for sprak 1.x, has been inlined in Apache Spark 2.x
-- Check project dependcy file: pom.xml, build.sbt, build.gradle etc
Example: spark-solr still uses spark 1.5 and use solr 6.x.

Skills for developers:
What's more important is how to debug and find the root cause.