[rules-users] BEST_FIT Null Pointer Exception

[Geoffrey De Smet]

> Exception in thread "main" java.lang.NullPointerException
> 	at
> com.example.domain.solver.MyVariableStrengthComparator.compare(MyVariableStrengthComparator.java:30)
That's an NPE in your code :)
(if that doesn't make any sense, any decent Java Programming 
course/tutorial should cover how to diagnose and fix that)

On 28-11-13 13:32, newbie wrote:
> Exception in thread "main" java.lang.NullPointerException
> 	at
> com.example.domain.solver.MyVariableStrengthComparator.compare(MyVariableStrengthComparator.java:30)
> 	at
> com.example.domain.solver.MyVariableStrengthComparator.compare(MyVariableStrengthComparator.java:1)
> 	at java.util.Arrays.mergeSort(Arrays.java:1270)
> 	at java.util.Arrays.mergeSort(Arrays.java:1282)
> 	at java.util.Arrays.mergeSort(Arrays.java:1282)
> 	at java.util.Arrays.mergeSort(Arrays.java:1282)
> 	at java.util.Arrays.mergeSort(Arrays.java:1282)
> 	at java.util.Arrays.sort(Arrays.java:1210)
> 	at java.util.Collections.sort(Collections.java:159)
> 	at
> org.optaplanner.core.impl.heuristic.selector.common.decorator.ComparatorSelectionSorter.sort(ComparatorSelectionSorter.java:28)
> 	at
> org.optaplanner.core.impl.heuristic.selector.value.decorator.SortingValueSelector.constructCache(SortingValueSelector.java:43)
> 	at
> org.optaplanner.core.impl.heuristic.selector.common.SelectionCacheLifecycleBridge.phaseStarted(SelectionCacheLifecycleBridge.java:48)
> 	at
> org.optaplanner.core.impl.phase.event.SolverPhaseLifecycleSupport.firePhaseStarted(SolverPhaseLifecycleSupport.java:41)
> 	at
> org.optaplanner.core.impl.heuristic.selector.AbstractSelector.phaseStarted(AbstractSelector.java:47)
> 	at
> org.optaplanner.core.impl.phase.event.SolverPhaseLifecycleSupport.firePhaseStarted(SolverPhaseLifecycleSupport.java:41)
> 	at
> org.optaplanner.core.impl.heuristic.selector.AbstractSelector.phaseStarted(AbstractSelector.java:47)
> 	at
> org.optaplanner.core.impl.heuristic.selector.value.decorator.ReinitializeVariableValueSelector.phaseStarted(ReinitializeVariableValueSelector.java:52)
> 	at
> org.optaplanner.core.impl.phase.event.SolverPhaseLifecycleSupport.firePhaseStarted(SolverPhaseLifecycleSupport.java:41)
> 	at
> org.optaplanner.core.impl.heuristic.selector.AbstractSelector.phaseStarted(AbstractSelector.java:47)
> 	at
> org.optaplanner.core.impl.phase.event.SolverPhaseLifecycleSupport.firePhaseStarted(SolverPhaseLifecycleSupport.java:41)
> 	at
> org.optaplanner.core.impl.heuristic.selector.AbstractSelector.phaseStarted(AbstractSelector.java:47)
> 	at
> org.optaplanner.core.impl.phase.event.SolverPhaseLifecycleSupport.firePhaseStarted(SolverPhaseLifecycleSupport.java:41)
> 	at
> org.optaplanner.core.impl.constructionheuristic.placer.AbstractEntityPlacer.phaseStarted(AbstractEntityPlacer.java:41)
> 	at
> org.optaplanner.core.impl.constructionheuristic.DefaultConstructionHeuristicSolverPhase.phaseStarted(DefaultConstructionHeuristicSolverPhase.java:120)
> 	at
> org.optaplanner.core.impl.constructionheuristic.DefaultConstructionHeuristicSolverPhase.solve(DefaultConstructionHeuristicSolverPhase.java:62)
> 	at
> org.optaplanner.core.impl.solver.DefaultSolver.runSolverPhases(DefaultSolver.java:190)
> 	at
> org.optaplanner.core.impl.solver.DefaultSolver.solve(DefaultSolver.java:155)
>
>
>
> --
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