избавляемся от странного кода

build.gradle

@@ -54,6 +54,8 @@ subprojects {
     }
 
     dependencies {
+        compile (group: 'org.jetbrains', name: 'annotations', version: '16.0.3')
+
         /* Logger */
         compile (group: 'org.slf4j', name: 'slf4j-api',      version: slf4j_version)
         compile (group: 'org.slf4j', name: 'jcl-over-slf4j', version: slf4j_version)

core/src/main/java/mc/core/network/NetInputStream.java

@@ -2,10 +2,11 @@ package mc.core.network;
 
 import lombok.Getter;
 import lombok.Setter;
+import org.jetbrains.annotations.NotNull;
 
-import java.io.IOException;
 import java.io.InputStream;
 import java.util.UUID;
+import java.util.concurrent.atomic.AtomicInteger;
 
 public abstract class NetInputStream extends InputStream {
     @Getter
@@ -23,7 +24,7 @@ public abstract class NetInputStream extends InputStream {
     public abstract short readShort();
     public abstract int readInt();
     public abstract int readVarInt();
-    public abstract int readVarInt(int[] countReadBytes);
+    public abstract int readVarInt(AtomicInteger countReadBytes);
     public abstract long readLong();
     public abstract float readFloat();
     public abstract double readDouble();
@@ -33,22 +34,22 @@ public abstract class NetInputStream extends InputStream {
     public abstract void skipBytes(int count);
 
     @Override
-    public int read() throws IOException {
+    public int read() {
         return readByte();
     }
 
     @Override
-    public int read(byte[] b) throws IOException {
+    public int read(@NotNull byte[] b) {
         return readBytes(b);
     }
 
     @Override
-    public int read(byte[] b, int off, int len) throws IOException {
+    public int read(@NotNull byte[] b, int off, int len) {
         return readBytes(b, off, len);
     }
 
     @Override
-    public long skip(long n) throws IOException {
+    public long skip(long n) {
         skipBytes((int) n);
         return n;
     }

proto_1.12.2/src/main/java/mc/core/network/proto_1_12_2/NetInputStream_p340.java

@@ -9,11 +9,12 @@ import mc.core.network.NetInputStream;
 
 import java.nio.charset.StandardCharsets;
 import java.util.UUID;
+import java.util.concurrent.atomic.AtomicInteger;
 
 @Slf4j
 public abstract class NetInputStream_p340 extends NetInputStream {
     @Override
-    public int readVarInt(int[] countReadBytes) {
+    public int readVarInt(AtomicInteger countReadBytes) {
         int numRead = 0;
         int result = 0;
         byte read;
@@ -29,7 +30,10 @@ public abstract class NetInputStream_p340 extends NetInputStream {
             numRead++;
         } while ((read & 0b10000000) != 0);
 
-        if (countReadBytes != null && countReadBytes.length == 1) countReadBytes[0] = numRead;
+        if (countReadBytes != null) {
+            countReadBytes.set(numRead);
+        }
+
         return result;
     }
 

proto_1.12.2_netty/src/main/java/mc/core/network/proto_1_12_2/netty/PacketDecoder.java

@@ -10,21 +10,21 @@ import mc.core.network.proto_1_12_2.State;
 import mc.core.network.proto_1_12_2.netty.wrappers.WrapperNetInputStream;
 
 import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import static mc.core.network.proto_1_12_2.netty.NettyServer.ATTR_STATE;
 
 @Slf4j
 public class PacketDecoder extends ReplayingDecoder<CSPacket> {
-    private int[] countReadBytes = new int[]{0};
 
     @Override
-    public void channelActive(ChannelHandlerContext ctx) throws Exception {
+    public void channelActive(ChannelHandlerContext ctx) {
         ctx.channel().attr(ATTR_STATE).set(State.HANDSHAKE);
         ctx.fireChannelActive();
     }
 
     @Override
-    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
+    public void channelInactive(ChannelHandlerContext ctx) {
         ctx.channel().attr(ATTR_STATE).set(null);
         ctx.fireChannelInactive();
     }
@@ -38,11 +38,12 @@ public class PacketDecoder extends ReplayingDecoder<CSPacket> {
         log.debug("Packet size: {}", packetSize);
         int leftDataPacket = packetSize;
 
+        final AtomicInteger countReadBytes = new AtomicInteger(0);
         int packetId = netStream.readVarInt(countReadBytes);
         String hexPacketId = Integer.toHexString(packetId).toUpperCase();
         if (hexPacketId.length() == 1) hexPacketId = "0" + hexPacketId;
         log.debug("Packet id: 0x{}", hexPacketId);
-        leftDataPacket = leftDataPacket - countReadBytes[0];
+        leftDataPacket = leftDataPacket - countReadBytes.get();
 
         Class<? extends CSPacket> packetClass = state.getClientSidePacket(packetId);
         if (packetClass == null) {