https://www.graalvm.org/ 
class com.oracle.truffle.polyglot.HostObject$IsArrayElementExisting
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.polyglot.HostObject$IsArrayElementExisting
  super_class: java.lang.Object
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.polyglot.HostObject$IsArrayElementExisting this
         0: .line 429
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.truffle.polyglot.HostObject$IsArrayElementExisting this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/polyglot/HostObject$IsArrayElementExisting;

  static boolean doArray(com.oracle.truffle.polyglot.HostObject, long, com.oracle.truffle.polyglot.HostObject$IsArrayNode);
    descriptor: (Lcom/oracle/truffle/polyglot/HostObject;JLcom/oracle/truffle/polyglot/HostObject$IsArrayNode;)Z
    flags: (0x0008) ACC_STATIC
    Code:
      stack=4, locals=6, args_size=3
        start local 0 // com.oracle.truffle.polyglot.HostObject receiver
        start local 1 // long index
        start local 3 // com.oracle.truffle.polyglot.HostObject$IsArrayNode isArray
         0: .line 434
            aload 0 /* receiver */
            getfield com.oracle.truffle.polyglot.HostObject.obj:Ljava/lang/Object;
            invokestatic java.lang.reflect.Array.getLength:(Ljava/lang/Object;)I
            i2l
            lstore 4 /* size */
        start local 4 // long size
         1: .line 435
            lload 1 /* index */
            lconst_0
            lcmp
            iflt 2
            lload 1 /* index */
            lload 4 /* size */
            lcmp
            ifge 2
            iconst_1
            ireturn
      StackMap locals: long
      StackMap stack:
         2: iconst_0
            ireturn
        end local 4 // long size
        end local 3 // com.oracle.truffle.polyglot.HostObject$IsArrayNode isArray
        end local 1 // long index
        end local 0 // com.oracle.truffle.polyglot.HostObject receiver
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    3     0  receiver  Lcom/oracle/truffle/polyglot/HostObject;
            0    3     1     index  J
            0    3     3   isArray  Lcom/oracle/truffle/polyglot/HostObject$IsArrayNode;
            1    3     4      size  J
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.dsl.Specialization(guards = {"isArray.execute(receiver)"}, limit = "1")
    RuntimeInvisibleParameterAnnotations: 
      0:
      1:
      2:
        com.oracle.truffle.api.dsl.Cached$Shared(value = "isArray")
        com.oracle.truffle.api.dsl.Cached()
    MethodParameters:
          Name  Flags
      receiver  
      index     
      isArray   

  static boolean doList(com.oracle.truffle.polyglot.HostObject, long, com.oracle.truffle.polyglot.HostObject$IsListNode);
    descriptor: (Lcom/oracle/truffle/polyglot/HostObject;JLcom/oracle/truffle/polyglot/HostObject$IsListNode;)Z
    flags: (0x0008) ACC_STATIC
    Code:
      stack=4, locals=6, args_size=3
        start local 0 // com.oracle.truffle.polyglot.HostObject receiver
        start local 1 // long index
        start local 3 // com.oracle.truffle.polyglot.HostObject$IsListNode isList
         0: .line 441
            aload 0 /* receiver */
            invokevirtual com.oracle.truffle.polyglot.HostObject.getListSize:()I
            i2l
            lstore 4 /* size */
        start local 4 // long size
         1: .line 442
            lload 1 /* index */
            lconst_0
            lcmp
            iflt 2
            lload 1 /* index */
            lload 4 /* size */
            lcmp
            ifge 2
            iconst_1
            ireturn
      StackMap locals: long
      StackMap stack:
         2: iconst_0
            ireturn
        end local 4 // long size
        end local 3 // com.oracle.truffle.polyglot.HostObject$IsListNode isList
        end local 1 // long index
        end local 0 // com.oracle.truffle.polyglot.HostObject receiver
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    3     0  receiver  Lcom/oracle/truffle/polyglot/HostObject;
            0    3     1     index  J
            0    3     3    isList  Lcom/oracle/truffle/polyglot/HostObject$IsListNode;
            1    3     4      size  J
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.dsl.Specialization(guards = {"isList.execute(receiver)"}, limit = "1")
    RuntimeInvisibleParameterAnnotations: 
      0:
      1:
      2:
        com.oracle.truffle.api.dsl.Cached$Shared(value = "isList")
        com.oracle.truffle.api.dsl.Cached()
    MethodParameters:
          Name  Flags
      receiver  
      index     
      isList    

  static boolean doNotArrayOrList(com.oracle.truffle.polyglot.HostObject, long, com.oracle.truffle.polyglot.HostObject$IsListNode, com.oracle.truffle.polyglot.HostObject$IsArrayNode);
    descriptor: (Lcom/oracle/truffle/polyglot/HostObject;JLcom/oracle/truffle/polyglot/HostObject$IsListNode;Lcom/oracle/truffle/polyglot/HostObject$IsArrayNode;)Z
    flags: (0x0008) ACC_STATIC
    Code:
      stack=1, locals=5, args_size=4
        start local 0 // com.oracle.truffle.polyglot.HostObject receiver
        start local 1 // long index
        start local 3 // com.oracle.truffle.polyglot.HostObject$IsListNode isList
        start local 4 // com.oracle.truffle.polyglot.HostObject$IsArrayNode isArray
         0: .line 449
            iconst_0
            ireturn
        end local 4 // com.oracle.truffle.polyglot.HostObject$IsArrayNode isArray
        end local 3 // com.oracle.truffle.polyglot.HostObject$IsListNode isList
        end local 1 // long index
        end local 0 // com.oracle.truffle.polyglot.HostObject receiver
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    1     0  receiver  Lcom/oracle/truffle/polyglot/HostObject;
            0    1     1     index  J
            0    1     3    isList  Lcom/oracle/truffle/polyglot/HostObject$IsListNode;
            0    1     4   isArray  Lcom/oracle/truffle/polyglot/HostObject$IsArrayNode;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.dsl.Specialization(guards = {"!isList.execute(receiver)", "!isArray.execute(receiver)"}, limit = "1")
    RuntimeInvisibleParameterAnnotations: 
      0:
      1:
      2:
        com.oracle.truffle.api.dsl.Cached$Shared(value = "isList")
        com.oracle.truffle.api.dsl.Cached()
      3:
        com.oracle.truffle.api.dsl.Cached$Shared(value = "isArray")
        com.oracle.truffle.api.dsl.Cached()
    MethodParameters:
          Name  Flags
      receiver  
      index     
      isList    
      isArray   
}
SourceFile: "HostObject.java"
NestHost: com.oracle.truffle.polyglot.HostObject
InnerClasses:
  public abstract Shared = com.oracle.truffle.api.dsl.Cached$Shared of com.oracle.truffle.api.dsl.Cached
  public abstract Repeat = com.oracle.truffle.api.library.ExportMessage$Repeat of com.oracle.truffle.api.library.ExportMessage
  IsArrayElementExisting = com.oracle.truffle.polyglot.HostObject$IsArrayElementExisting of com.oracle.truffle.polyglot.HostObject
  abstract IsArrayNode = com.oracle.truffle.polyglot.HostObject$IsArrayNode of com.oracle.truffle.polyglot.HostObject
  abstract IsListNode = com.oracle.truffle.polyglot.HostObject$IsListNode of com.oracle.truffle.polyglot.HostObject
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportMessage$Repeat(value = {com.oracle.truffle.api.library.ExportMessage(name = "isArrayElementReadable"), com.oracle.truffle.api.library.ExportMessage(name = "isArrayElementModifiable")})