# Error while starting logstash netflow module
**URL:** https://discuss.elastic.co/t/error-while-starting-logstash-netflow-module/202802
**Category:** Logstash
**Created:** [October 9, 2019, 9:36am UTC](https://discuss.elastic.co/t/error-while-starting-logstash-netflow-module/202802 "2019-10-09T09:36:39Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Vikash\_Singh1](https://discuss.elastic.co/u/Vikash_Singh1)
#### Post date: [October 9, 2019, 9:36am UTC](https://discuss.elastic.co/t/error-while-starting-logstash-netflow-module/202802/1 "2019-10-09T09:36:39Z")
Somehow after updating the logstash-7.3 to 7.4 I am getting error while starting the logstash. I have checked the logs and the error is: [ERROR] 2019-10-09 15:04:46.938 [\java.lang.ClassCastException: org.jruby.gen.RubyObject4 cannot be cast to org.jruby.RubyFixnum, "backtrace"=\>["org.jruby.runtime.invokedynamic.MathLinker.fixnum\_op\_div(MathLinker.java:233)", "java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)", "org.jruby.runtime.invokedynamic.MathLinker.fixnumOperator(MathLinker.java:171)", "usr.share.logstash.vendor.bundle.jruby.$2\_dot\_5\_dot\_0.gems.logstash\_minus\_codec\_minus\_netflow\_minus\_4\_dot\_2\_dot\_1.lib.logstash.codecs.netflow.RUBY$block$decode\_netflow5$2(/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-codec-netflow-4.2.1/lib/logstash/codecs/netflow.rb:139)", "org.jruby.runtime.CompiledIRBlockBody.yieldDirect(CompiledIRBlockBody.java:146)", "org.jruby.runtime.BlockBody.yield(BlockBody.java:114)", "org.jruby.runtime.Block.yield(Block.java:170)", "org.jruby.ir.runtime.IRRuntimeHelpers.yield(IRRuntimeHelpers.java:477)", "org.jruby.ir.targets.YieldSite.yield(YieldSite.java:105)", "usr.share.logstash.vendor.bundle.jruby.$2\_dot\_5\_dot\_0.gems.bindata\_minus\_2\_dot\_4\_dot\_4.lib.bindata.struct.RUBY$block$each\_pair$0(/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/bindata-2.4.4/lib/bindata/struct.rb:169)", "org.jruby.runtime.CompiledIRBlockBody.yieldDirect(CompiledIRBlockBody.java:146)", "org.jruby.runtime.MixedModeIRBlockBody.yieldDirect(MixedModeIRBlockBody.java:124)", "org.jruby.runtime.BlockBody.yield(BlockBody.java:114)", "org.jruby.runtime.Block.yield(Block.java:170)", "org.jruby.RubyArray.each(RubyArray.java:1800)", "org.jruby.RubyArray$INVOKER$i$0$0$each.call(RubyArray$INVOKER$i$0$0$each.gen)", "org.jruby.internal.runtime.methods.JavaMethod$JavaMethodZeroBlock.call(JavaMethod.java:555)", "org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:332)", "org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:86)", "org.jruby.runtime.callsite.CachingCallSite.callIter(CachingCallSite.java:93)", "org.jruby.ir.instructions.CallBase.interpret(CallBase.java:537)", "org.jruby.ir.interpreter.InterpreterEngine.processCall(InterpreterEngine.java:361)", "org.jruby.ir.interpreter.StartupInterpreterEngine.interpret(StartupInterpreterEngine.java:72)", "org.jruby.internal.runtime.methods.MixedModeIRMethod.INTERPRET\_METHOD(MixedModeIRMethod.java:105)", "org.jruby.internal.runtime.methods.MixedModeIRMethod.call(MixedModeIRMethod.java:92)", "org.jruby.ir.targets.InvokeSite.invoke(InvokeSite.java:177)", "usr.share.logstash.vendor.bundle.jruby.$2\_dot\_5\_dot\_0.gems.logstash\_minus\_codec\_minus\_netflow\_minus\_4\_dot\_2\_dot\_1.lib.logstash.codecs.netflow.RUBY$method$decode\_netflow5$0(/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-codec-netflow-4.2.1/lib/logstash/codecs/netflow.rb:130)", "usr.share.logstash.vendor.bundle.jruby.$2\_dot\_5\_dot\_0.gems.logstash\_minus\_codec\_minus\_netflow\_minus\_4\_dot\_2\_dot\_1.lib.logstash.codecs.netflow.RUBY$method$decode\_netflow5$0$ **VARARGS** (/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-codec-netflow-4.2.1/lib/logstash/codecs/netflow.rb)", "org.jruby.internal.runtime.methods.CompiledIRMethod.call(CompiledIRMethod.java:91)", "org.jruby.internal.runtime.methods.MixedModeIRMethod.call(MixedModeIRMethod.java:90)", "org.jruby.ir.targets.InvokeSite.invoke(InvokeSite.java:183)", "usr.share.logstash.vendor.bundle.jruby.$2\_dot\_5\_dot\_0.gems.logstash\_minus\_codec\_minus\_netflow\_minus\_4\_dot\_2\_dot\_1.lib.logstash.codecs.netflow.RUBY$block$decode$1(/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-codec-netflow-4.2.1/lib/logstash/codecs/netflow.rb:88)", "org.jruby.runtime.CompiledIRBlockBody.yieldDirect(CompiledIRBlockBody.java:146)", "org.jruby.runtime.BlockBody.yield(BlockBody.java:114)", "org.jruby.runtime.Block.yield(Block.java:170)", "org.jruby.ir.runtime.IRRuntimeHelpers.yield(IRRuntimeHelpers.java:477)", "org.jruby.ir.instructions.YieldInstr.interpret(YieldInstr.java:85)", "org.jruby.ir.interpreter.StartupInterpreterEngine.processOtherOp(StartupInterpreterEngine.java:178)", "org.jruby.ir.interpreter.StartupInterpreterEngine.interpret(StartupInterpreterEngine.java:104)", "org.jruby.ir.interpreter.Interpreter.INTERPRET\_BLOCK(Interpreter.java:114)", "org.jruby.runtime.MixedModeIRBlockBody.commonYieldPath(MixedModeIRBlockBody.java:151)", "org.jruby.runtime.IRBlockBody.doYield(IRBlockBody.java:187)", "org.jruby.runtime.BlockBody.yield(BlockBody.java:116)", "org.jruby.runtime.Block.yield(Block.java:170)", "org.jruby.RubyArray.each(RubyArray.java:1800)", "org.jruby.RubyArray$INVOKER$i$0$0$each.call(RubyArray$INVOKER$i$0$0$each.gen)", "org.jruby.internal.runtime.methods.JavaMethod$JavaMethodZeroBlock.call(JavaMethod.java:555)", "org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:332)", "org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:86)", "org.jruby.runtime.callsite.CachingCallSite.callIter(CachingCallSite.java:93)", "org.jruby.ir.instructions.CallBase.interpret(CallBase.java:537)", "org.jruby.ir.interpreter.InterpreterEngine.processCall(InterpreterEngine.java:361)", "org.jruby.ir.interpreter.StartupInterpreterEngine.interpret(StartupInterpreterEngine.java:72)", "org.jruby.internal.runtime.methods.MixedModeIRMethod.INTERPRET\_METHOD(MixedModeIRMethod.java:105)", "org.jruby.internal.runtime.methods.MixedModeIRMethod.call(MixedModeIRMethod.java:92)", "org.jruby.ir.targets.InvokeSite.invoke(InvokeSite.java:177)", "usr.share.logstash.vendor.bundle.jruby.$2\_dot\_5\_dot\_0.gems.logstash\_minus\_codec\_minus\_netflow\_minus\_4\_dot\_2\_dot\_1.lib.logstash.codecs.netflow.RUBY$method$decode$0(/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-codec-netflow-4.2.1/lib/logstash/codecs/netflow.rb:87)", "usr.share.logstash.logstash\_minus\_core.lib.logstash.codecs.delegator.RUBY$block$decode$1(/usr/share/logstash/logstash-core/lib/logstash/codecs/delegator.rb:45)", "org.jruby.runtime.CompiledIRBlockBody.callDirect(CompiledIRBlockBody.java:136)", "org.jruby.runtime.IRBlockBody.call(IRBlockBody.java:77)", "org.jruby.runtime.IRBlockBody.call(IRBlockBody.java:51)", "org.jruby.runtime.Block.call(Block.java:133)", "org.logstash.instrument.metrics.MetricExt.doTime(MetricExt.java:140)", "org.logstash.instrument.metrics.AbstractSimpleMetricExt.time(AbstractSimpleMetricExt.java:45)", "org.logstash.instrument.metrics.NamespacedMetricExt.doTime(NamespacedMetricExt.java:87)", "org.logstash.instrument.metrics.AbstractNamespacedMetricExt.time(AbstractNamespacedMetricExt.java:44)",
Can i get some help on this???
---
### Author:  [@Vikash\_Singh1](https://discuss.elastic.co/u/Vikash_Singh1)
#### Post date: [October 9, 2019, 9:37am UTC](https://discuss.elastic.co/t/error-while-starting-logstash-netflow-module/202802/2 "2019-10-09T09:37:29Z")
I have trying updating the logstash-plugin but that doesn't help too..
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### Author:  [@PhaedrusTheGreek](https://discuss.elastic.co/u/PhaedrusTheGreek)
#### Post date: [October 16, 2019, 3:17pm UTC](https://discuss.elastic.co/t/error-while-starting-logstash-netflow-module/202802/3 "2019-10-16T15:17:30Z")
> [@Vikash\_Singh1](#):
>
> java.lang.ClassCastException: org.jruby.gen.RubyObject4 cannot be cast to org.jruby.RubyFixnum
Tracking [Here](https://github.com/elastic/logstash/issues/11196)
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 13, 2019, 3:28pm UTC](https://discuss.elastic.co/t/error-while-starting-logstash-netflow-module/202802/4 "2019-11-13T15:28:21Z")
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