ArrayIndexOutOfBoundsException

[GabrielSin]

My trade system was not working , I made some changes and it worked . But always when I confirm the trade is with 1 or 2 player I get this error. More does not affect anything in return, it just appears that message. I think my PacketReader is correct too.

java.lang.ArrayIndexOutOfBoundsException: 4
	at handling.mina.PacketReader.readDatatype(PacketReader.java:46)
	at handling.mina.PacketReader.readShort(PacketReader.java:54)
	at handling.channel.handler.PlayerInteractionHandler.PlayerInteraction(PlayerInteractionHandler.java:353)
	at handling.MapleServerHandler.handlePacket(MapleServerHandler.java:546)
	at handling.MapleServerHandler.messageReceived(MapleServerHandler.java:190)
	at org.apache.mina.common.support.AbstractIoFilterChain$TailFilter.messageReceived(AbstractIoFilterChain.java:570)
	at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageReceived(AbstractIoFilterChain.java:299)
	at org.apache.mina.common.support.AbstractIoFilterChain.access$1100(AbstractIoFilterChain.java:53)
	at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.messageReceived(AbstractIoFilterChain.java:648)
	at org.apache.mina.filter.codec.support.SimpleProtocolDecoderOutput.flush(SimpleProtocolDecoderOutput.java:58)
	at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:180)
	at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageReceived(AbstractIoFilterChain.java:299)
	at org.apache.mina.common.support.AbstractIoFilterChain.access$1100(AbstractIoFilterChain.java:53)
	at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.messageReceived(AbstractIoFilterChain.java:648)
	at org.apache.mina.filter.executor.ExecutorFilter.processEvent(ExecutorFilter.java:220)
	at org.apache.mina.filter.executor.ExecutorFilter$ProcessEventsRunnable.run(ExecutorFilter.java:264)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:51)
	at java.lang.Thread.run(Unknown Source)

PlayerInteractionHandler.java:353

short bundles = slea.readShort();

PacketReader.java:54

    public short readShort() {
        return (short)readDatatype(2);
    }

PacketReader.java:46

    private int readDatatype(int count) {
        int ret = message[index++] & 0xFF;
        for (int i = 1; i <= count - 1; i++) {
            ret += ((message[index++] & 0xFF) << 8*i);
        }
        return ret;
    }

 

[SYJourney]

First off, that's a really confusing way to parse a number, why not just do:

int ret = 0;
for (int i = 0; i < count; i++) {
     ret += (message[index] & 0xFF) << (8 * i);
     index++;
}
return ret;

I see that you are using it for short, but are you using it for long too? That would cause an overflow because the return type is int.

But other than that I see nothing wrong in the code itself. Most likely index is already 2 when reading the short, so next it tries to read index 3/4 and then you get ArrayIndexOutOfBoundsException: 4. So for some reason, you don't actually have more than 3 bytes available, possibly because you are in the wrong branch of the handler (PlayerInteractionHandler does like 10+ things IIRC).