We Keep Coding

when I run a simple program in Junit, it is giving me this error. I already inserted jar files and configured my build path

java.lang.NoClassDefFoundError: org/junit/platform/engine/ConfigurationParameters
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.(JUnit5TestLoader.java:34)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:78)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
at java.base/java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:128)
at java.base/jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:350)
at java.base/java.lang.Class.newInstance(Class.java:642)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createRawTestLoader(RemoteTestRunner.java:371)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createLoader(RemoteTestRunner.java:366)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.defaultInit(RemoteTestRunner.java:310)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.init(RemoteTestRunner.java:225)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)
Caused by: java.lang.ClassNotFoundException: org.junit.platform.engine.ConfigurationParameters
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:636)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:182)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
... 13 more

How do we resolve JUnit Mockito not being found in Eclipse?

Here is my error message:
java.lang.TypeNotPresentException: Type MockitoJUnitRunner not present
at java.base/sun.reflect.annotation.TypeNotPresentExceptionProxy.generateException(TypeNotPresentExceptionProxy.java:46)
at java.base/sun.reflect.annotation.AnnotationInvocationHandler.invoke(AnnotationInvocationHandler.java:86)
at com.sun.proxy.$Proxy2.value(Unknown Source)
at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:70)
at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:37)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:70)
at org.junit.internal.requests.ClassRequest.createRunner(ClassRequest.java:28)
at org.junit.internal.requests.MemoizingRequest.getRunner(MemoizingRequest.java:19)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createUnfilteredTest(JUnit4TestLoader.java:90)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:76)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:49)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:513)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:756)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:452)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)
Caused by: java.lang.ClassNotFoundException: MockitoJUnitRunner
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:398)
at java.base/sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:114)
at java.base/sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:125)
at java.base/sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49)
at java.base/sun.reflect.annotation.AnnotationParser.parseSig(AnnotationParser.java:440)
at java.base/sun.reflect.annotation.AnnotationParser.parseClassValue(AnnotationParser.java:421)
at java.base/sun.reflect.annotation.AnnotationParser.parseMemberValue(AnnotationParser.java:350)
at java.base/sun.reflect.annotation.AnnotationParser.parseAnnotation2(AnnotationParser.java:287)
at java.base/sun.reflect.annotation.AnnotationParser.parseAnnotations2(AnnotationParser.java:121)
at java.base/sun.reflect.annotation.AnnotationParser.parseAnnotations(AnnotationParser.java:73)
at java.base/java.lang.Class.createAnnotationData(Class.java:3757)
at java.base/java.lang.Class.annotationData(Class.java:3746)
at java.base/java.lang.Class.getAnnotation(Class.java:3651)
at org.junit.internal.builders.IgnoredBuilder.runnerForClass(IgnoredBuilder.java:10)
... 12 more
mockitojunitrunner is not present error

NoClassDefFoundError when trying to register a listener to an EventBus (Google Guava)

In a project for college we have to implement participants which can exchange messages via a channel. This channel has to be realised as a EventBus (Guava).
When I'm trying to register a listener (part1) to the eventbus (channel):
channel.register(part1);
the following Exception appears in the console.
Exception in thread "main" java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:1051)
Caused by: java.lang.RuntimeException: Exception in Application start method
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:900)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:195)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.NoClassDefFoundError: com/google/common/util/concurrent/internal/InternalFutureFailureAccess
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1095)
at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:206)
at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:759)
at java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:680)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:605)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:579)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1095)
at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:206)
at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:759)
at java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:680)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:605)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:579)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1095)
at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:206)
at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:759)
at java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:680)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:605)
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:579)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at com.google.common/com.google.common.cache.LocalCache$LoadingValueReference.<init>(LocalCache.java:3472)
at com.google.common/com.google.common.cache.LocalCache$LoadingValueReference.<init>(LocalCache.java:3476)
at com.google.common/com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2134)
at com.google.common/com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2045)
at com.google.common/com.google.common.cache.LocalCache.get(LocalCache.java:3951)
at com.google.common/com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3974)
at com.google.common/com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4958)
at com.google.common/com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:4964)
at com.google.common/com.google.common.eventbus.SubscriberRegistry.getAnnotatedMethods(SubscriberRegistry.java:173)
at com.google.common/com.google.common.eventbus.SubscriberRegistry.findAllSubscribers(SubscriberRegistry.java:164)
at com.google.common/com.google.common.eventbus.SubscriberRegistry.register(SubscriberRegistry.java:74)
at com.google.common/com.google.common.eventbus.EventBus.register(EventBus.java:186)
at commands.Commands.createChannel(Commands.java:243)
at persistence.HSQLDB.resetDatabase(HSQLDB.java:482)
at gui.GUI.start(GUI.java:101)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:846)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:455)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run$$$capture(InvokeLaterDispatcher.java:96)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
... 1 more
Caused by: java.lang.ClassNotFoundException: com.google.common.util.concurrent.internal.InternalFutureFailureAccess
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
... 55 more
Can anyone help me?
The guava.jar is added as a library. It has to be something with the implementation of the jar and the ClassLoader.

Guava has one real dependency that is needed at runtime: com.google.guava:failureaccess.
You'll need to download that jar and put it on your classpath, too.
(As Onur Baştürk suggests, this happens automatically with some build tools.)

log4jdbc Java 8 compatibility

I'm trying to monitor my MySQL database queries using log4jdbc. I have a WSO2 Identity server running with Java 8. I followed the instructions in [1] and getting the following error.
[2019-01-11 15:19:37,590] ERROR {org.wso2.carbon.user.core.common.DefaultRealm} - nullType class java.lang.reflect.InvocationTargetException
org.wso2.carbon.user.core.UserStoreException: nullType class java.lang.reflect.InvocationTargetException
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:395)
at org.wso2.carbon.user.core.common.DefaultRealm.initializeObjects(DefaultRealm.java:222)
at org.wso2.carbon.user.core.common.DefaultRealm.init(DefaultRealm.java:127)
at org.wso2.carbon.user.core.common.DefaultRealmService.initializeRealm(DefaultRealmService.java:264)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:102)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:115)
at org.wso2.carbon.user.core.internal.Activator.startDeploy(Activator.java:72)
at org.wso2.carbon.user.core.internal.BundleCheckActivator.start(BundleCheckActivator.java:61)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683)
at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:390)
at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1176)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:559)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:544)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:457)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:438)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:349)
... 22 more
Caused by: org.wso2.carbon.user.core.UserStoreException: Error occurred while checking is existing domain : PRIMARY for tenant : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:837)
at org.wso2.carbon.user.core.common.AbstractUserStoreManager.persistDomain(AbstractUserStoreManager.java:6028)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:297)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:239)
... 27 more
Caused by: org.wso2.carbon.user.core.UserStoreException: DB error occurred while checking is existing domain : PRIMARY & tenant id : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:989)
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:825)
... 30 more
Caused by: java.sql.SQLException: net.sf.log4jdbc.sql.jdbcapi.DriverSpy cannot be found by jdbc-pool_7.0.81.wso2v2
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:254)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:730)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:664)
at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:200)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:127)
at org.wso2.carbon.user.core.util.DatabaseUtil.getDBConnection(DatabaseUtil.java:868)
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:971)
... 31 more
Caused by: java.lang.ClassNotFoundException: net.sf.log4jdbc.sql.jdbcapi.DriverSpy cannot be found by jdbc-pool_7.0.81.wso2v2
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:501)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:421)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:412)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:246)
... 38 more
[2019-01-11 15:19:37,603] ERROR {org.wso2.carbon.user.core.internal.Activator} - Cannot start User Manager Core bundle
org.wso2.carbon.user.core.UserStoreException: Cannot initialize the realm.
at org.wso2.carbon.user.core.common.DefaultRealmService.initializeRealm(DefaultRealmService.java:274)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:102)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:115)
at org.wso2.carbon.user.core.internal.Activator.startDeploy(Activator.java:72)
at org.wso2.carbon.user.core.internal.BundleCheckActivator.start(BundleCheckActivator.java:61)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683)
at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:390)
at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1176)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:559)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:544)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:457)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:438)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
Caused by: org.wso2.carbon.user.core.UserStoreException: nullType class java.lang.reflect.InvocationTargetException
at org.wso2.carbon.user.core.common.DefaultRealm.initializeObjects(DefaultRealm.java:316)
at org.wso2.carbon.user.core.common.DefaultRealm.init(DefaultRealm.java:127)
at org.wso2.carbon.user.core.common.DefaultRealmService.initializeRealm(DefaultRealmService.java:264)
... 19 more
Caused by: org.wso2.carbon.user.core.UserStoreException: nullType class java.lang.reflect.InvocationTargetException
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:395)
at org.wso2.carbon.user.core.common.DefaultRealm.initializeObjects(DefaultRealm.java:222)
... 21 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:349)
... 22 more
Caused by: org.wso2.carbon.user.core.UserStoreException: Error occurred while checking is existing domain : PRIMARY for tenant : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:837)
at org.wso2.carbon.user.core.common.AbstractUserStoreManager.persistDomain(AbstractUserStoreManager.java:6028)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:297)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:239)
... 27 more
Caused by: org.wso2.carbon.user.core.UserStoreException: DB error occurred while checking is existing domain : PRIMARY & tenant id : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:989)
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:825)
... 30 more
Caused by: java.sql.SQLException: net.sf.log4jdbc.sql.jdbcapi.DriverSpy cannot be found by jdbc-pool_7.0.81.wso2v2
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:254)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:730)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:664)
at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:200)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:127)
at org.wso2.carbon.user.core.util.DatabaseUtil.getDBConnection(DatabaseUtil.java:868)
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:971)
... 31 more
Caused by: java.lang.ClassNotFoundException: net.sf.log4jdbc.sql.jdbcapi.DriverSpy cannot be found by jdbc-pool_7.0.81.wso2v2
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:501)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:421)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:412)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:246)
... 38 more
My log4jdbc version is log4jdbc4-1.2.jar. Any help is appreciated. Thanks in advance.
http://msmshariq.blogspot.com/2015/03/troubleshooting-wso2-server-database.html

It's a class not found error. Can you try with this class name?
<driverClassName>net.sf.log4jdbc.DriverSpy</driverClassName>
Ref: http://movingaheadblog.blogspot.com/2016/07/how-to-use-log4jdbc-with-wso2-products_28.html

WSO2-wso2am-2.1.0 API manager!!! Failed to start wso2 API Manager

./wso2server.sh
While am running sudo sh wso2server.sh
[2018-10-04 09:27:43,575] INFO - TemplateDeployerServiceTrackerDS Successfully deployed the execution manager tracker service
[2018-10-04 09:27:45,052] ERROR - DefaultRealm nullType class java.lang.reflect.InvocationTargetException
org.wso2.carbon.user.core.UserStoreException: nullType class java.lang.reflect.InvocationTargetException
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:401)
at org.wso2.carbon.user.core.common.DefaultRealm.initializeObjects(DefaultRealm.java:222)
at org.wso2.carbon.user.core.common.DefaultRealm.init(DefaultRealm.java:127)
at org.wso2.carbon.user.core.common.DefaultRealmService.initializeRealm(DefaultRealmService.java:263)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:100)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:113)
at org.wso2.carbon.user.core.internal.Activator.startDeploy(Activator.java:68)
at org.wso2.carbon.user.core.internal.BundleCheckActivator.start(BundleCheckActivator.java:61)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683)
at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:390)
at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1176)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:559)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:544)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:457)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:438)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:355)
... 22 more
Caused by: org.wso2.carbon.user.core.UserStoreException: Error occurred while checking is existing domain : PRIMARY for tenant : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:839)
at org.wso2.carbon.user.core.common.AbstractUserStoreManager.persistDomain(AbstractUserStoreManager.java:4064)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:280)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:222)
... 27 more
Caused by: org.wso2.carbon.user.core.UserStoreException: DB error occurred while checking is existing domain : PRIMARY & tenant id : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:991)
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:827)
... 30 more
Caused by: java.sql.SQLException: com.mysql.jdbc.Driver cannot be found by jdbc-pool_7.0.34.wso2v2
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:254)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:701)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:635)
at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:188)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:127)
at org.wso2.carbon.user.core.util.DatabaseUtil.getDBConnection(DatabaseUtil.java:565)
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:973)
... 31 more
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver cannot be found by jdbc-pool_7.0.34.wso2v2
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:501)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:421)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:412)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:246)
... 38 more
[2018-10-04 09:27:45,060] ERROR - Activator Cannot start User Manager Core bundle
org.wso2.carbon.user.core.UserStoreException: Cannot initialize the realm.
at org.wso2.carbon.user.core.common.DefaultRealmService.initializeRealm(DefaultRealmService.java:273)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:100)
at org.wso2.carbon.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:113)
at org.wso2.carbon.user.core.internal.Activator.startDeploy(Activator.java:68)
at org.wso2.carbon.user.core.internal.BundleCheckActivator.start(BundleCheckActivator.java:61)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683)
at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:390)
at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1176)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:559)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:544)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:457)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:438)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
Caused by: org.wso2.carbon.user.core.UserStoreException: nullType class java.lang.reflect.InvocationTargetException
at org.wso2.carbon.user.core.common.DefaultRealm.initializeObjects(DefaultRealm.java:322)
at org.wso2.carbon.user.core.common.DefaultRealm.init(DefaultRealm.java:127)
at org.wso2.carbon.user.core.common.DefaultRealmService.initializeRealm(DefaultRealmService.java:263)
... 19 more
Caused by: org.wso2.carbon.user.core.UserStoreException: nullType class java.lang.reflect.InvocationTargetException
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:401)
at org.wso2.carbon.user.core.common.DefaultRealm.initializeObjects(DefaultRealm.java:222)
... 21 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.wso2.carbon.user.core.common.DefaultRealm.createObjectWithOptions(DefaultRealm.java:355)
... 22 more
Caused by: org.wso2.carbon.user.core.UserStoreException: Error occurred while checking is existing domain : PRIMARY for tenant : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:839)
at org.wso2.carbon.user.core.common.AbstractUserStoreManager.persistDomain(AbstractUserStoreManager.java:4064)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:280)
at org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.<init>(JDBCUserStoreManager.java:222)
... 27 more
Caused by: org.wso2.carbon.user.core.UserStoreException: DB error occurred while checking is existing domain : PRIMARY & tenant id : -1234
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:991)
at org.wso2.carbon.user.core.util.UserCoreUtil.persistDomain(UserCoreUtil.java:827)
... 30 more
Caused by: java.sql.SQLException: com.mysql.jdbc.Driver cannot be found by jdbc-pool_7.0.34.wso2v2
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:254)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:701)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:635)
at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:188)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:127)
at org.wso2.carbon.user.core.util.DatabaseUtil.getDBConnection(DatabaseUtil.java:565)
at org.wso2.carbon.user.core.util.UserCoreUtil.isExistingDomain(UserCoreUtil.java:973)
... 31 more
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver cannot be found by jdbc-pool_7.0.34.wso2v2
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:501)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:421)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:412)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:246)
... 38 more
[2018-10-04 09:27:55,695] INFO - TaglibUriRule TLD skipped. URI: http://tiles.apache.org/tags-tiles is already defined

Seems you have configured a MySQL database, but have not copied the MySQL driver jar to the repository/components/lib/.
Try that.