OptaPlanner got java reflection error in Spring boot

I just tried to run an OptaPlanner project in Spring Boot, but there's only very simple text in OptaPlanner User Guide for Spring.

Actually, I think it is very easy to copy all domain objects, configuration files and drools files from an OptaPlanner project to Spring Boot project without any changes, but the only question is how to call Solver's solve method.

I made it run after Spring Boot startup with a class (named CommandLineAppStartupRunner) which implements CommandLineRunner interface, and I called solve method in its run method. Finally, I got an exception like follows:

Caused by: java.lang.IllegalArgumentException: Can not set org.optaplanner.core.api.score.buildin.hardmediumsoft.HardMediumSoftScore field springbootcloudbalance.domain.CloudBalance.score to springbootcloudbalance.domain.CloudBalance
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171)
at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:58)
at sun.reflect.UnsafeObjectFieldAccessorImpl.get(UnsafeObjectFieldAccessorImpl.java:36)
at java.lang.reflect.Field.get(Field.java:393)
at org.optaplanner.core.impl.domain.common.accessor.ReflectionFieldMemberAccessor.executeGetter(ReflectionFieldMemberAccessor.java:54)
at org.optaplanner.core.impl.domain.solution.descriptor.SolutionDescriptor.getScore(SolutionDescriptor.java:1071)
at org.optaplanner.core.impl.score.director.AbstractScoreDirector.cloneSolution(AbstractScoreDirector.java:212)
at org.optaplanner.core.impl.solver.scope.DefaultSolverScope.setWorkingSolutionFromBestSolution(DefaultSolverScope.java:230)
at org.optaplanner.core.impl.solver.AbstractSolver.solvingStarted(AbstractSolver.java:75)
at org.optaplanner.core.impl.solver.DefaultSolver.solvingStarted(DefaultSolver.java:210)
at org.optaplanner.core.impl.solver.DefaultSolver.solve(DefaultSolver.java:190)
at springbootcloudbalance.CommandLineAppStartupRunner.run(CommandLineAppStartupRunner.java:55)
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:818)
... 10 common frames omitted

I checked the code, and found the exception throws because the object from field.getDeclaringClass() is a different instance from the one from var1.getClass(). I'm afraid it due to the implementation of java reflection conflicts between OptaPlanner and Spring Boot.

The version I used is as follows:

• OptaPlanner 7.11.0.Final
• Spring Boot 2.0.5.RELEASE
• JVM 1.8.0_181