https://openjdk.java.net/ 
public class jdk.nashorn.internal.runtime.regexp.joni.encoding.IntHolder
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: jdk.nashorn.internal.runtime.regexp.joni.encoding.IntHolder
  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 // jdk.nashorn.internal.runtime.regexp.joni.encoding.IntHolder this
         0: .line 23
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // jdk.nashorn.internal.runtime.regexp.joni.encoding.IntHolder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Ljdk/nashorn/internal/runtime/regexp/joni/encoding/IntHolder;
}
SourceFile: "IntHolder.java"