https://www.graalvm.org/ 
interface com.oracle.truffle.nfi.test.StringAsInterfaceNFITest$StdLib
  minor version: 0
  major version: 59
  flags: flags: (0x0600) ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.nfi.test.StringAsInterfaceNFITest$StdLib
  super_class: java.lang.Object
{
  public abstract java.lang.Object malloc(int);
    descriptor: (I)Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      size  

  public abstract void free(java.lang.Object);
    descriptor: (Ljava/lang/Object;)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
         Name  Flags
      pointer  

  public abstract java.lang.String strdup(java.lang.String);
    descriptor: (Ljava/lang/String;)Ljava/lang/String;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      orig  
}
SourceFile: "StringAsInterfaceNFITest.java"
NestHost: com.oracle.truffle.nfi.test.StringAsInterfaceNFITest
InnerClasses:
  abstract StdLib = com.oracle.truffle.nfi.test.StringAsInterfaceNFITest$StdLib of com.oracle.truffle.nfi.test.StringAsInterfaceNFITest
  public abstract Implementable = org.graalvm.polyglot.HostAccess$Implementable of org.graalvm.polyglot.HostAccess
    RuntimeVisibleAnnotations: 
      org.graalvm.polyglot.HostAccess$Implementable()