Apache Camel throws FileNotFoundException when processing in multiple threads - apache-camel

Question

I use the following configuration to process files in 4 parallel threads:
<route id="input-decision" errorHandlerRef="inputDeadLetterHandler">
<from ref="file:${input.directory}?maxMessagesPerPoll=${input.pollSize}&delay=${input.delay}&move=${input.processedDirectory}/$simple{date:now:yyyy-MM-dd}/$simple{file:name}&sortBy=file:name&renameUsingCopy=true&antExclude=*.tmp"/>
<threads maxPoolSize="4" poolSize="4">
<!-- processing file here -->
</threads>
</route>
And it begins to throw exceptions constantly like the one below in several seconds after startup:
org.apache.camel.TypeConversionException: Error during type conversion from type: java.lang.String to the required type: byte[] with value [Body is file based: GenericFile[send_output_20141210134657_73 145.xml]] due java.io.FileNotFoundException: send_output_20141210134657_73 145.xml
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.createTypeConversionException(BaseTypeConverterRegistry.java:566) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.mandatoryConvertTo(BaseTypeConverterRegistry.java:174) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.component.file.FileBinding.loadContent(FileBinding.java:57) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.component.file.GenericFileConverter.genericFileToInputStream(GenericFileConverter.java:123) ~[camel-core-2.14.0.jar:2.14.0]
at sun.reflect.GeneratedMethodAccessor117.invoke(Unknown Source) ~[na:na]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_71]
at java.lang.reflect.Method.invoke(Method.java:606) ~[na:1.7.0_71]
at org.apache.camel.util.ObjectHelper.invokeMethod(ObjectHelper.java:1002) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.StaticMethodTypeConverter.convertTo(StaticMethodTypeConverter.java:59) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.doConvertTo(BaseTypeConverterRegistry.java:276) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.convertTo(BaseTypeConverterRegistry.java:114) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.MessageSupport.getBody(MessageSupport.java:72) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.MessageSupport.getBody(MessageSupport.java:47) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.builder.xml.XPathBuilder.doInEvaluateAs(XPathBuilder.java:876) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.builder.xml.XPathBuilder.evaluateAs(XPathBuilder.java:774) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.builder.xml.XPathBuilder.matches(XPathBuilder.java:157) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.processor.ChoiceProcessor.process(ChoiceProcessor.java:90) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:72) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:398) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191) [camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.processor.Pipeline.process(Pipeline.java:118) [camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.processor.Pipeline.access$100(Pipeline.java:43) [camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.processor.Pipeline$1.done(Pipeline.java:136) [camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.processor.ThreadsProcessor$ProcessCall.run(ThreadsProcessor.java:83) [camel-core-2.14.0.jar:2.14.0]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [na:1.7.0_71]
at java.util.concurrent.FutureTask.run(FutureTask.java:262) [na:1.7.0_71]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_71]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_71]
at java.lang.Thread.run(Thread.java:745) [na:1.7.0_71]
Caused by: org.apache.camel.RuntimeCamelException: java.io.FileNotFoundException: send_output_20141210134657_73 145.xml
at org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException(ObjectHelper.java:1364) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.util.ObjectHelper.invokeMethod(ObjectHelper.java:1006) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.StaticMethodTypeConverter.convertTo(StaticMethodTypeConverter.java:59) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.component.file.GenericFileConverter.convertTo(GenericFileConverter.java:97) ~[camel-core-2.14.0.jar:2.14.0]
at sun.reflect.GeneratedMethodAccessor44.invoke(Unknown Source) ~[na:na]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_71]
at java.lang.reflect.Method.invoke(Method.java:606) ~[na:1.7.0_71]
at org.apache.camel.util.ObjectHelper.invokeMethod(ObjectHelper.java:1002) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.StaticMethodFallbackTypeConverter.convertTo(StaticMethodFallbackTypeConverter.java:62) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.doConvertTo(BaseTypeConverterRegistry.java:316) ~[camel-core-2.14.0.jar:2.14.0]
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.mandatoryConvertTo(BaseTypeConverterRegistry.java:165) ~[camel-core-2.14.0.jar:2.14.0]
... 27 common frames omitted
Removing <threads> element helps, but this slows down the speed of exchange. Also, using seda: endpoint instead of threads helps, but it does not guarantee delivery between reboots, i.e. if I shutdown Camel when it processes a message from seda:, it won't recover it on startup, that means that a message is lost. Also I tried ActiveMQ, but it seems to be overkill for just processing files simulteneously. Besides, I have some problems with ActiveMQ as well.