https://www.graalvm.org/ 
interface com.oracle.svm.tutorial.CInterfaceTutorial$Substruct2 extends org.graalvm.word.PointerBase
  minor version: 0
  major version: 59
  flags: flags: (0x0600) ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.svm.tutorial.CInterfaceTutorial$Substruct2
  super_class: java.lang.Object
{
  public abstract com.oracle.svm.tutorial.CInterfaceTutorial$Header header();
    descriptor: ()Lcom/oracle/svm/tutorial/CInterfaceTutorial$Header;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.struct.CFieldAddress()

  public abstract int offsetOfHeader();
    descriptor: ()I
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.struct.CFieldOffset(value = "header")

  public abstract int f1();
    descriptor: ()I
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.struct.CField()

  public abstract org.graalvm.word.UnsignedWord offsetOff1();
    descriptor: ()Lorg/graalvm/word/UnsignedWord;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.struct.CFieldOffset()
}
SourceFile: "CInterfaceTutorial.java"
NestHost: com.oracle.svm.tutorial.CInterfaceTutorial
InnerClasses:
  abstract Header = com.oracle.svm.tutorial.CInterfaceTutorial$Header of com.oracle.svm.tutorial.CInterfaceTutorial
  abstract Substruct2 = com.oracle.svm.tutorial.CInterfaceTutorial$Substruct2 of com.oracle.svm.tutorial.CInterfaceTutorial
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.struct.CStruct(value = "subdata_t")