Moving an Item out of Inventory creates Exception

[fionera]

2018-08-30 13:25:23.875 ERROR 19626 --- [ playerExec1] .a.i.SimpleAsyncUncaughtExceptionHandler : Unexpected error occurred invoking async method: public void rocks.cleanstone.player.listener.CreativeInventoryActionListener.onCreativeInventoryAction(rocks.cleanstone.player.event.PlayerInboundPacketEvent)

java.lang.ArrayIndexOutOfBoundsException: -1
at rocks.cleanstone.game.inventory.SimpleInventory.setItemInSlot(SimpleInventory.java:41) ~[classes/:na]
at rocks.cleanstone.player.listener.CreativeInventoryActionListener.onCreativeInventoryAction(CreativeInventoryActionListener.java:19) ~[classes/:na]
at rocks.cleanstone.player.listener.CreativeInventoryActionListener$$FastClassBySpringCGLIB$$f91b7df8.invoke() ~[classes/:na]
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[spring-core-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:746) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_171]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[na:1.8.0_171]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[na:1.8.0_171]
at java.lang.Thread.run(Thread.java:748) ~[na:1.8.0_171]