http://netty.io/netty-all/: Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers and clients. (The Netty Project) 
public abstract class io.netty.util.AbstractReferenceCounted implements io.netty.util.ReferenceCounted
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: io.netty.util.AbstractReferenceCounted
  super_class: java.lang.Object
{
  private static final java.util.concurrent.atomic.AtomicIntegerFieldUpdater<io.netty.util.AbstractReferenceCounted> refCntUpdater;
    descriptor: Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    Signature: Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater<Lio/netty/util/AbstractReferenceCounted;>;

  private volatile int refCnt;
    descriptor: I
    flags: (0x0042) ACC_PRIVATE, ACC_VOLATILE

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=0, args_size=0
         0: .line 28
            ldc Lio/netty/util/AbstractReferenceCounted;
            ldc "refCnt"
            invokestatic java.util.concurrent.atomic.AtomicIntegerFieldUpdater.newUpdater:(Ljava/lang/Class;Ljava/lang/String;)Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
         1: .line 27
            putstatic io.netty.util.AbstractReferenceCounted.refCntUpdater:Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
         2: .line 28
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // io.netty.util.AbstractReferenceCounted this
         0: .line 25
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 30
            aload 0 /* this */
            iconst_1
            putfield io.netty.util.AbstractReferenceCounted.refCnt:I
         2: .line 25
            return
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lio/netty/util/AbstractReferenceCounted;

  public final int refCnt();
    descriptor: ()I
    flags: (0x0011) ACC_PUBLIC, ACC_FINAL
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // io.netty.util.AbstractReferenceCounted this
         0: .line 34
            aload 0 /* this */
            getfield io.netty.util.AbstractReferenceCounted.refCnt:I
            ireturn
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/util/AbstractReferenceCounted;

  protected final void setRefCnt(int);
    descriptor: (I)V
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // io.netty.util.AbstractReferenceCounted this
        start local 1 // int refCnt
         0: .line 41
            getstatic io.netty.util.AbstractReferenceCounted.refCntUpdater:Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
            aload 0 /* this */
            iload 1 /* refCnt */
            invokevirtual java.util.concurrent.atomic.AtomicIntegerFieldUpdater.set:(Ljava/lang/Object;I)V
         1: .line 42
            return
        end local 1 // int refCnt
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    2     0    this  Lio/netty/util/AbstractReferenceCounted;
            0    2     1  refCnt  I
    MethodParameters:
        Name  Flags
      refCnt  

  public io.netty.util.ReferenceCounted retain();
    descriptor: ()Lio/netty/util/ReferenceCounted;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // io.netty.util.AbstractReferenceCounted this
         0: .line 46
            aload 0 /* this */
            iconst_1
            invokevirtual io.netty.util.AbstractReferenceCounted.retain0:(I)Lio/netty/util/ReferenceCounted;
            areturn
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/util/AbstractReferenceCounted;

  public io.netty.util.ReferenceCounted retain(int);
    descriptor: (I)Lio/netty/util/ReferenceCounted;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // io.netty.util.AbstractReferenceCounted this
        start local 1 // int increment
         0: .line 51
            aload 0 /* this */
            iload 1 /* increment */
            ldc "increment"
            invokestatic io.netty.util.internal.ObjectUtil.checkPositive:(ILjava/lang/String;)I
            invokevirtual io.netty.util.AbstractReferenceCounted.retain0:(I)Lio/netty/util/ReferenceCounted;
            areturn
        end local 1 // int increment
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    1     0       this  Lio/netty/util/AbstractReferenceCounted;
            0    1     1  increment  I
    MethodParameters:
           Name  Flags
      increment  

  private io.netty.util.ReferenceCounted retain0(int);
    descriptor: (I)Lio/netty/util/ReferenceCounted;
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=4, locals=3, args_size=2
        start local 0 // io.netty.util.AbstractReferenceCounted this
        start local 1 // int increment
         0: .line 55
            getstatic io.netty.util.AbstractReferenceCounted.refCntUpdater:Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
            aload 0 /* this */
            iload 1 /* increment */
            invokevirtual java.util.concurrent.atomic.AtomicIntegerFieldUpdater.getAndAdd:(Ljava/lang/Object;I)I
            istore 2 /* oldRef */
        start local 2 // int oldRef
         1: .line 56
            iload 2 /* oldRef */
            ifle 2
            iload 2 /* oldRef */
            iload 1 /* increment */
            iadd
            iload 2 /* oldRef */
            if_icmpge 4
         2: .line 58
      StackMap locals: int
      StackMap stack:
            getstatic io.netty.util.AbstractReferenceCounted.refCntUpdater:Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
            aload 0 /* this */
            iload 1 /* increment */
            ineg
            invokevirtual java.util.concurrent.atomic.AtomicIntegerFieldUpdater.getAndAdd:(Ljava/lang/Object;I)I
            pop
         3: .line 59
            new io.netty.util.IllegalReferenceCountException
            dup
            iload 2 /* oldRef */
            iload 1 /* increment */
            invokespecial io.netty.util.IllegalReferenceCountException.<init>:(II)V
            athrow
         4: .line 61
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            areturn
        end local 2 // int oldRef
        end local 1 // int increment
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    5     0       this  Lio/netty/util/AbstractReferenceCounted;
            0    5     1  increment  I
            1    5     2     oldRef  I
    MethodParameters:
           Name  Flags
      increment  

  public io.netty.util.ReferenceCounted touch();
    descriptor: ()Lio/netty/util/ReferenceCounted;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // io.netty.util.AbstractReferenceCounted this
         0: .line 66
            aload 0 /* this */
            aconst_null
            invokevirtual io.netty.util.AbstractReferenceCounted.touch:(Ljava/lang/Object;)Lio/netty/util/ReferenceCounted;
            areturn
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/util/AbstractReferenceCounted;

  public boolean release();
    descriptor: ()Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // io.netty.util.AbstractReferenceCounted this
         0: .line 71
            aload 0 /* this */
            iconst_1
            invokevirtual io.netty.util.AbstractReferenceCounted.release0:(I)Z
            ireturn
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/util/AbstractReferenceCounted;

  public boolean release(int);
    descriptor: (I)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // io.netty.util.AbstractReferenceCounted this
        start local 1 // int decrement
         0: .line 76
            aload 0 /* this */
            iload 1 /* decrement */
            ldc "decrement"
            invokestatic io.netty.util.internal.ObjectUtil.checkPositive:(ILjava/lang/String;)I
            invokevirtual io.netty.util.AbstractReferenceCounted.release0:(I)Z
            ireturn
        end local 1 // int decrement
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    1     0       this  Lio/netty/util/AbstractReferenceCounted;
            0    1     1  decrement  I
    MethodParameters:
           Name  Flags
      decrement  

  private boolean release0(int);
    descriptor: (I)Z
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=4, locals=3, args_size=2
        start local 0 // io.netty.util.AbstractReferenceCounted this
        start local 1 // int decrement
         0: .line 80
            getstatic io.netty.util.AbstractReferenceCounted.refCntUpdater:Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
            aload 0 /* this */
            iload 1 /* decrement */
            ineg
            invokevirtual java.util.concurrent.atomic.AtomicIntegerFieldUpdater.getAndAdd:(Ljava/lang/Object;I)I
            istore 2 /* oldRef */
        start local 2 // int oldRef
         1: .line 81
            iload 2 /* oldRef */
            iload 1 /* decrement */
            if_icmpne 4
         2: .line 82
            aload 0 /* this */
            invokevirtual io.netty.util.AbstractReferenceCounted.deallocate:()V
         3: .line 83
            iconst_1
            ireturn
         4: .line 84
      StackMap locals: int
      StackMap stack:
            iload 2 /* oldRef */
            iload 1 /* decrement */
            if_icmplt 5
            iload 2 /* oldRef */
            iload 1 /* decrement */
            isub
            iload 2 /* oldRef */
            if_icmple 7
         5: .line 86
      StackMap locals:
      StackMap stack:
            getstatic io.netty.util.AbstractReferenceCounted.refCntUpdater:Ljava/util/concurrent/atomic/AtomicIntegerFieldUpdater;
            aload 0 /* this */
            iload 1 /* decrement */
            invokevirtual java.util.concurrent.atomic.AtomicIntegerFieldUpdater.getAndAdd:(Ljava/lang/Object;I)I
            pop
         6: .line 87
            new io.netty.util.IllegalReferenceCountException
            dup
            iload 2 /* oldRef */
            iload 1 /* decrement */
            ineg
            invokespecial io.netty.util.IllegalReferenceCountException.<init>:(II)V
            athrow
         7: .line 89
      StackMap locals:
      StackMap stack:
            iconst_0
            ireturn
        end local 2 // int oldRef
        end local 1 // int decrement
        end local 0 // io.netty.util.AbstractReferenceCounted this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    8     0       this  Lio/netty/util/AbstractReferenceCounted;
            0    8     1  decrement  I
            1    8     2     oldRef  I
    MethodParameters:
           Name  Flags
      decrement  

  protected abstract void deallocate();
    descriptor: ()V
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT
}
SourceFile: "AbstractReferenceCounted.java"