https://www.graalvm.org/ 
interface com.oracle.truffle.polyglot.FileSystems$InternalFileSystem extends org.graalvm.polyglot.io.FileSystem
  minor version: 0
  major version: 59
  flags: flags: (0x0600) ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.polyglot.FileSystems$InternalFileSystem
  super_class: java.lang.Object
{
  public abstract boolean hasAllAccess();
    descriptor: ()Z
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "FileSystems.java"
NestHost: com.oracle.truffle.polyglot.FileSystems
InnerClasses:
  private abstract InternalFileSystem = com.oracle.truffle.polyglot.FileSystems$InternalFileSystem of com.oracle.truffle.polyglot.FileSystems