Optaplanner - Null Pointer Exception from AbstractTabuAcceptor class in default environment mode - optaplanner

I thought this question has been fixed by v7 as this JIRA story: https://issues.jboss.org/browse/PLANNER-757, but when I use nullable = True in planning variable with Tabu search, it still throws null pointer error in the 'adjustTabuList' method. Has anyone else encountered the same issue?


What might cause IndexOutOfRangeException at System.Runtime.Caching.UsageBucket.GetFreeUsageEntry()

I have an azure webapp and sometimes(rarely), I am getting below exception:
Index was outside the bounds of the array.
System.IndexOutOfRangeException at System.Runtime.Caching.UsageBucket.GetFreeUsageEntry() at System.Runtime.Caching.UsageBucket.AddCacheEntry(MemoryCacheEntry cacheEntry) at System.Runtime.Caching.MemoryCacheStore.AddToCache(MemoryCacheEntry entry) at System.Runtime.Caching.MemoryCacheStore.Set(MemoryCacheKey key, MemoryCacheEntry entry) at System.Runtime.Caching.MemoryCache.Set(String key, Object value, CacheItemPolicy policy, String regionName)
This happens very rarely but once it happens, it keeps happening until the affected webapp instance is restarted.
I can't find any documentation about this UsageBucket APIs. If anybody has any idea about its root cause, please let me know.

Get broken constrains in OptaPanner with non-reversible accumulator

I am trying to obtains list of broken constrains from a problem instance in OptaPlanner. I am using OptaPlanner version 7.0.0.Final and drools for rules engine (also 7.0.0.Final). The problem is solved correctly and without any error, but when I try to obtain broken constrains I get a NullPointer exception.
As far as I have researched, I found out, that this only happens, when I use drools accumulator without reverse operation (like max or min). Further I have made a custom accumulator, which is the exact copy from org.drools.core.base.accumulators.LongSumAccumulateFunction and everything works as expected, but as soon as I change the supportsReverse() function to return false, the NullPointer exception rises.
I have managed to reconstruct this problem in one of the provided examples - CloudBalancing. This is the change to CloudBalancingHelloWorld, it's only purpose is to obtain list of broken constraints as mentioned in this post.
public class CloudBalancingHelloWorld {
public static void main(String[] args) {
// Build the Solver
SolverFactory<CloudBalance> solverFactory = SolverFactory.createFromXmlResource(
Solver<CloudBalance> solver = solverFactory.buildSolver();
// Load a problem with 400 computers and 1200 processes
CloudBalance unsolvedCloudBalance = new CloudBalancingGenerator().createCloudBalance(400, 1200);
// Solve the problem
CloudBalance solvedCloudBalance = solver.solve(unsolvedCloudBalance);
// Display the result
System.out.println("\nSolved cloudBalance with 400 computers and 1200 processes:\n"
+ toDisplayString(solvedCloudBalance));
//A Piece of code added - start
ScoreDirector<CloudBalance> scoreDirector = solver.getScoreDirectorFactory().buildScoreDirector();
Collection<ConstraintMatchTotal> constrains = scoreDirector.getConstraintMatchTotals();
//A Piece of code added - end
public static String toDisplayString(CloudBalance cloudBalance) {
StringBuilder displayString = new StringBuilder();
for (CloudProcess process : cloudBalance.getProcessList()) {
CloudComputer computer = process.getComputer();
displayString.append(" ").append(process.getLabel()).append(" -> ")
.append(computer == null ? null : computer.getLabel()).append("\n");
return displayString.toString();
And this is the change to requiredCpoPowerTotal rule. Please note that I have done this only to demonstrate the problem. Basicaly I have changed sum to max.
rule "requiredCpuPowerTotal"
$computer : CloudComputer($cpuPower : cpuPower)
computer == $computer,
$requiredCpuPower : requiredCpuPower);
$requiredCpuPowerTotal : max($requiredCpuPower);
(Integer) $requiredCpuPowerTotal > $cpuPower
scoreHolder.addHardConstraintMatch(kcontext, $cpuPower - (Integer) $requiredCpuPowerTotal);
I am really confused, because the error does not happen during planing phase, but when the scoreDirector recomputes the score to obtain broken constrains it does. I mean the same calculations must have happened during the planning phase right?
Anyway here is the stack trace
Exception in thread "main" Exception executing consequence for rule "requiredCpuPowerTotal" in org.optaplanner.examples.cloudbalancing.solver: java.lang.NullPointerException
at org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.core.common.DefaultAgenda.handleException(DefaultAgenda.java:1256)
at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:438)
at org.drools.core.phreak.RuleExecutor.fireActivation(RuleExecutor.java:379)
at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:135)
at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:88)
at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:34)
at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1072)
at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1019)
at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1011)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1321)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1312)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1296)
at org.optaplanner.core.impl.score.director.drools.DroolsScoreDirector.getConstraintMatchTotals(DroolsScoreDirector.java:134)
at org.optaplanner.examples.cloudbalancing.app.CloudBalancingHelloWorld.main(CloudBalancingHelloWorld.java:52)
Caused by: java.lang.NullPointerException
at org.drools.core.base.accumulators.JavaAccumulatorFunctionExecutor$JavaAccumulatorFunctionContext.getAccumulatedObjects(JavaAccumulatorFunctionExecutor.java:208)
at org.drools.core.reteoo.FromNodeLeftTuple.getAccumulatedObjects(FromNodeLeftTuple.java:94)
at org.drools.core.common.AgendaItem.getObjectsDeep(AgendaItem.java:78)
at org.drools.core.reteoo.RuleTerminalNodeLeftTuple.getObjectsDeep(RuleTerminalNodeLeftTuple.java:359)
at org.optaplanner.core.api.score.holder.AbstractScoreHolder.extractJustificationList(AbstractScoreHolder.java:118)
at org.optaplanner.core.api.score.holder.AbstractScoreHolder.registerConstraintMatch(AbstractScoreHolder.java:88)
at org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScoreHolder.addHardConstraintMatch(HardSoftScoreHolder.java:53)
at org.optaplanner.examples.cloudbalancing.solver.Rule_requiredCpuPowerTotal1284553313.defaultConsequence(Rule_requiredCpuPowerTotal1284553313.java:14)
at org.optaplanner.examples.cloudbalancing.solver.Rule_requiredCpuPowerTotal1284553313DefaultConsequenceInvokerGenerated.evaluate(Unknown Source)
at org.optaplanner.examples.cloudbalancing.solver.Rule_requiredCpuPowerTotal1284553313DefaultConsequenceInvoker.evaluate(Unknown Source)
at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:431)
... 13 more
Thank you for any help in advance.
That NPE sounds like a bug in Drools. The ConstraintMatch API should always just work. Very that you get it against the latest master version. If so, please create a jira for this with a minimal reproducer and we'll look into it.

Crash with Lucene.NET when using Sort

I have a date field inserted in a Lucene database with the following code:
Document.Add(new NumericField("TimeStamp", Field.Store.YES, true).SetLongValue(Data.TimeStamp.ToBinary()));
And I have the following query:
var Sort = new Sort(new SortField("TimeStamp", SortField.LONG, true));
var ParsedQuery = ParseQuery(_Parser, SearchQuery);
var Filter = new QueryWrapperFilter(ParsedQuery);
var Hits = _Searcher.Search(ParsedQuery, Filter, Skip + Limit, Sort);
But it crashes when executing the search method with the following:
A first chance exception of type 'Lucene.Net.QueryParsers.QueryParser.LookaheadSuccess' occurred in Lucene.Net.dll
A first chance exception of type 'System.IO.IOException' occurred in Lucene.Net.dll
A first chance exception of type 'System.IO.IOException' occurred in Lucene.Net.dll
A first chance exception of type 'System.AccessViolationException' occurred in HDIndexing.dll
Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
If I replace the Sort variable with one of the constants, such as Sort.RELEVANCE then the search works properly.
The problem comes from my custom search.
Incidentally I noticed something else odd and I do not know if these is a connection: If I inspect my Lucene DB with the Luke tool, all my fields are reported to be strings:
I do not know if this is a bug in Luke or something is wrong with how Lucene is set up on my end.
I tried to change the sort to a type 'string' to see what would happen, but it crashes the same way, so either way, the type of the field doesn't seem to have an impact.
Has anyone experienced that problem before?
It could be similar to someone else's post: lucene.net sort not working access violation

Mongoose idGetter error: Cannot set property '_id' of null

I am getting the following error from the Mongoose idGetter function. Can anyone shed some light on what may be causing it?
return this.$__._id = null == this._id
TypeError: Cannot set property '_id' of null
at model.idGetter (e:\Users\Christine\test\mvt\node_modules\mongoose\lib\schema.js:98:23)
The error situation involves multiple client requests performing document removes (on different documents in the same collection), on a database being accessed over internet (i.e. slow response time). The failure happens on accessing the id of one of the removed documents. There appears to be a small timing window in which it occurs - everything I've tried to debug it causes the problem to 'go away'.
Outline of the application code:
Details.findOneAndRemove({ _id : remove_id}, afterRemove);
function afterRemove(err, removedDoc){
if (!err && removedDoc){
OtherDetails.find({ _id: some_id}, afterFind);
function afterFind(err, foundDoc){
if (!err && foundDoc){
// next line causes exception
if (foundDoc.details_id === removedDoc.id) { // do stuff };
Do you have an id property defined on the document that you have removed?
If not, you should probably want to compare foundDoc.details_id with removedDoc._id
Below is the source code for the idGetter function in the mongoose code base:
function idGetter () {
if (this.$__._id) {
return this.$__._id;
return this.$__._id = null == this._id
? null
: String(this._id);
As I understand, I think that the idGetter is specifically aimed at ObjectId types, hence that exception.
You could also try to add an id property on the document if it does not yet exist to see if it continues to throw the same exception.
fwiw: it is possible that the problem was related to using 32-bit Node on 64-bit Windows (8.1). After installing 64-bit Node, I could not reproduce the problem.
Unsatisfying level of certainty, but I thought I would share in case anyone else gets a similar problem or can shed light on whether this might really have been the cause.

Ravendb Issues with nullables when creating Map/Reduce index

I'm trying to create an index with map/reduce using the AbstractIndexCreationTask class.
however it seems that I have issues related to nullables, inside the Map's linq query:
For the following let sentence I get (in studio's index view) 2 errors of
"Nullable object must have a value":
let isOk = Something1.HasValue && Something2.HasValue (When both Somethings are of nullable int type)
For the following let sentence I get the following error when executing - "System.InvalidOperationException: Could not understand query: "
let result = isOk ? Result.result1 : (Result?)null (when Result is a nullable enum - it seems that the problem occurs due to the returned casted null)
I've experienced this issues in ver 2.0, and currently on latest client version from NuGet: 2.5.2666
I will appreciate your help.
Instead of HasValue, use != null