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 final class io.netty.util.internal.IntegerHolder
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: io.netty.util.internal.IntegerHolder
  super_class: java.lang.Object
{
  public int value;
    descriptor: I
    flags: (0x0001) ACC_PUBLIC

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // io.netty.util.internal.IntegerHolder this
         0: .line 19
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // io.netty.util.internal.IntegerHolder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/util/internal/IntegerHolder;
}
SourceFile: "IntegerHolder.java"