How I can fix this? I'm using Magma 1.12.2 and ProtocolLib 4.80

If this problem hasn't already been reported, please open a ticket
at https://github.com/dmulloy2/ProtocolLib/issues with the following data:
Stack Trace:
java.lang.RuntimeException: Error occured while instancing generated class.
at com.comphenix.protocol.reflect.compiler.StructureCompiler.compile(StructureCompiler.java:249)
at com.comphenix.protocol.reflect.compiler.CompiledStructureModifier.withTarget(CompiledStructureModifier.java:130)
at com.comphenix.protocol.events.PacketContainer.(PacketContainer.java:139)
at com.comphenix.protocol.injector.netty.ProtocolInjector.onPacketReceiving(ProtocolInjector.java:324)
at com.comphenix.protocol.injector.netty.ChannelInjector.decode(ChannelInjector.java:600)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:411)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:248)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at com.comphenix.protocol.injector.netty.ChannelInjector$2.channelRead(ChannelInjector.java:292)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:280)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:396)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:248)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at net.minecraft.network.LegacyPingHandler.channelRead(SourceFile:94)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:287)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1334)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:926)
at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:1017)
at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:394)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:299)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.comphenix.protocol.reflect.compiler.StructureCompiler.compile(StructureCompiler.java:233)
... 37 more
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_12_R1/PacketHandshakingInSetProtocol
at com.comphenix.protocol.reflect.compiler.CompiledStructure$net_minecraft_network_handshake_client_C00Handshake$java_lang_Object.(Unknown Source)
... 42 more
Dump:
Parameters:
io.netty.buffer.PooledUnsafeDirectByteBuf@42e6d221[
memoryAddress=140566777819152
recyclerHandle=io.netty.util.Recycler$DefaultHandle@60b0c1fc
chunk=Chunk(11ac83bb: 1%, 106496/16777216)
handle=4611686018427389953
memory=java.nio.DirectByteBuffer[pos=0 lim=16777216 cap=16777216]
offset=8192
length=19
maxLength=32
cache=io.netty.buffer.PoolThreadCache@5e7c0b2f
tmpNioBuf=java.nio.DirectByteBuffer[pos=8208 lim=8208 cap=16777216]
allocator=PooledByteBufAllocator(directByDefault: true)
refCnt=1
readerIndex=19
writerIndex=19
markedReaderIndex=0
markedWriterIndex=0
maxCapacity=2147483647
]
manager:
com.comphenix.protocol.injector.PacketFilterManager@117eb66d[
unhookTask=com.comphenix.protocol.injector.DelayedSingleTask@740a918c
packetListeners=[PacketAdapter[plugin=LoginSecurity, sending=ListeningWhitelist[priority=LOW, packets=[WINDOW_ITEMS[class=PacketPlayOutWindowItems, id=20], SET_SLOT[class=PacketPlayOutSetSlot, id=22], WINDOW_DATA[class=PacketPlayOutWindowData, id=21]], gamephase=PLAYING, options=[]], receiving=EMPTY_WHITELIST], PacketAdapter[plugin=ServerListPlus, sending=ListeningWhitelist[priority=NORMAL, packets=[OUT_SERVER_INFO[class=PacketStatusOutServerInfo, id=0], SET_PROTOCOL[class=PacketHandshakingInSetProtocol, id=0]], gamephase=PLAYING, options=[ASYNC]], receiving=ListeningWhitelist[priority=NORMAL, packets=[OUT_SERVER_INFO[class=PacketStatusOutServerInfo, id=0], SET_PROTOCOL[class=PacketHandshakingInSetProtocol, id=0]], gamephase=PLAYING, options=[ASYNC]]]]
packetInjector=com.comphenix.protocol.injector.netty.ProtocolInjector$5@6eb74447
playerInjection=com.comphenix.protocol.injector.netty.ProtocolInjector$4@119a91dc
inputBufferedPackets=[]
recievedListeners=com.comphenix.protocol.injector.SortedPacketListenerList@7533905c
sendingListeners=com.comphenix.protocol.injector.SortedPacketListenerList@5515f987
hasClosed=false
classLoader=org.bukkit.plugin.java.PluginClassLoader@1ab2ff1d
reporter=com.comphenix.protocol.ProtocolLib$1@1d41a1e
server=CraftServer{serverName=Magma,serverVersion=1.12.2-866f4a2c,minecraftVersion=1.12.2}
library=ProtocolLib v4.8.0-b547
asyncFilterManager=com.comphenix.protocol.async.AsyncFilterManager@2d5db635
knowsServerPackets=true
knowsClientPackets=true
phaseLoginCount=2
phasePlayingCount=3
packetCreation=false
nettyInjector=com.comphenix.protocol.injector.netty.ProtocolInjector@59e1eeb4
pluginVerifier=com.comphenix.protocol.injector.PluginVerifier@7be3be3b
hasRecycleDistance=true
minecraftVersion=(MC: 1.12.2)
debug=false
]
Sender:
com.comphenix.protocol.injector.netty.ChannelInjector@205a340d[
decodeBuffer=protected void net.minecraft.network.NettyPacketDecoder.decode(io.netty.channel.ChannelHandlerContext,io.netty.buffer.ByteBuf,java.util.List) throws java.lang.Exception
encodeBuffer=protected void net.minecraft.network.NettyPacketEncoder.encode(io.netty.channel.ChannelHandlerContext,java.lang.Object,io.netty.buffer.ByteBuf) throws java.lang.Exception
factory=com.comphenix.protocol.injector.netty.InjectionFactory@262bd6a7
player=com.comphenix.protocol.injector.server.TemporaryPlayerInvocationHandler@220ebfa0
updated=
playerName=
playerConnection=
networkManager=net.minecraft.network.NetworkManager@1dd0e0f9
originalChannel=[id: 0xfff094e5, L:/172.18.0.10:25573 - R:/104.243.38.184:34936]
channelField=VolatileField [accessor=DefaultFieldAccessor [field=public io.netty.channel.Channel net.minecraft.network.NetworkManager.field_150746_k], container=net.minecraft.network.NetworkManager@1dd0e0f9, previous=[id: 0xfff094e5, L:/172.18.0.10:25573 - R:/104.243.38.184:34936], current=com.comphenix.protocol.injector.netty.ChannelInjector$3@32f36795, previousLoaded=true, currentSet=true, forceAccess=true]
packetMarker={}
currentEvent=
finalEvent=
unfilteredProcessedPackets=com.comphenix.protocol.injector.netty.PacketFilterQueue@65d72dd4
vanillaDecoder=net.minecraft.network.NettyPacketDecoder@7f9acebf
vanillaEncoder=net.minecraft.network.NettyPacketEncoder@7a2a6576
finishQueue=[]
channelListener=com.comphenix.protocol.injector.netty.ProtocolInjector@59e1eeb4
processor=com.comphenix.protocol.injector.NetworkProcessor@fa94459
injected=true
closed=false
cumulation=PooledUnsafeDirectByteBuf(ridx: 19, widx: 19, cap: 19)
cumulator=io.netty.handler.codec.ByteToMessageDecoder$1@4876a78d
singleDecode=false
decodeWasNull=false
first=true
discardAfterReads=16
numReads=0
added=true
]
Version:
ProtocolLib v4.8.0-b547
Java Version:
1.8.0_312
Server:
1.12.2-866f4a2c (MC: 1.12.2)

We are currently not supporting magma, and there are no plans to support magma in the near future. Please use a fork of craftbukkit (like spigot or paper) to get support.