java - Course timetabling and Conference scheduling examples are broken in OptaPlanner 8.0.0 final (Windows 10)

Question

I downloaded the project for the first time, installed latest Java jre1.8.0_271 and these examples crash. Anyone knows which version of Java will run this?

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at org.drools.compiler.commons.jci.compilers.NativeJavaCompiler.compile(NativeJavaCompiler.java:85)
at org.drools.compiler.commons.jci.compilers.AbstractJavaCompiler.compile(AbstractJavaCompiler.java:49)
at org.drools.modelcompiler.builder.CanonicalModelKieProject.writeProjectOutput(CanonicalModelKieProject.java:99)
at org.drools.compiler.kie.builder.impl.KieBuilderImpl.buildKieProject(KieBuilderImpl.java:285)
at org.drools.compiler.kie.builder.impl.KieBuilderImpl.buildAll(KieBuilderImpl.java:247)
at org.drools.compiler.kie.builder.impl.KieBuilderImpl.buildAll(KieBuilderImpl.java:204)
at org.optaplanner.core.impl.score.director.ScoreDirectorFactoryFactory.buildDroolsScoreDirectorFactory(ScoreDirectorFactoryFactory.java:254)
at org.optaplanner.core.impl.score.director.ScoreDirectorFactoryFactory.decideMultipleScoreDirectorFactories(ScoreDirectorFactoryFactory.java:109)
at org.optaplanner.core.impl.score.director.ScoreDirectorFactoryFactory.buildScoreDirectorFactory(ScoreDirectorFactoryFactory.java:74)
at org.optaplanner.core.impl.solver.DefaultSolverFactory.buildScoreDirectorFactory(DefaultSolverFactory.java:115)
at org.optaplanner.core.impl.solver.DefaultSolverFactory.buildSolver(DefaultSolverFactory.java:83)
at org.optaplanner.examples.common.business.SolutionBusiness.setSolver(SolutionBusiness.java:189)
at org.optaplanner.examples.common.app.CommonApp.createSolutionBusiness(CommonApp.java:128)
at org.optaplanner.examples.common.app.CommonApp.init(CommonApp.java:116)
at org.optaplanner.examples.app.OptaPlannerExamplesApp$1.actionPerformed(OptaPlannerExamplesApp.java:155)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

You have to use JDK (Java Development Kit), not JRE. You can get OpenJDK at https://adoptopenjdk.net/. OpenJDK 11 or higher is recommended but OptaPlanner 8.x runs on Java 8 as well.