https://www.graalvm.org/ 
final class com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext
  super_class: java.lang.Object
{
  final org.graalvm.polyglot.io.FileSystem fileSystem;
    descriptor: Lorg/graalvm/polyglot/io/FileSystem;
    flags: (0x0010) ACC_FINAL

  final java.util.Map<java.lang.String, com.oracle.truffle.polyglot.LanguageCache> cachedLanguages;
    descriptor: Ljava/util/Map;
    flags: (0x0010) ACC_FINAL
    Signature: Ljava/util/Map<Ljava/lang/String;Lcom/oracle/truffle/polyglot/LanguageCache;>;

  final java.util.function.Supplier<java.util.Map<java.lang.String, java.util.Collection<? extends com.oracle.truffle.api.TruffleFile$FileTypeDetector>>> fileTypeDetectors;
    descriptor: Ljava/util/function/Supplier;
    flags: (0x0010) ACC_FINAL
    Signature: Ljava/util/function/Supplier<Ljava/util/Map<Ljava/lang/String;Ljava/util/Collection<+Lcom/oracle/truffle/api/TruffleFile$FileTypeDetector;>;>;>;

  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext this
         0: .line 333
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 335
            aload 0 /* this */
            invokestatic com.oracle.truffle.polyglot.FileSystems.newDefaultFileSystem:()Lorg/graalvm/polyglot/io/FileSystem;
            putfield com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext.fileSystem:Lorg/graalvm/polyglot/io/FileSystem;
         2: .line 336
            aload 0 /* this */
            invokestatic com.oracle.truffle.polyglot.LanguageCache.languages:()Ljava/util/Map;
            putfield com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext.cachedLanguages:Ljava/util/Map;
         3: .line 337
            aload 0 /* this */
            aload 0 /* this */
            getfield com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext.cachedLanguages:Ljava/util/Map;
            invokeinterface java.util.Map.values:()Ljava/util/Collection;
            invokestatic com.oracle.truffle.polyglot.FileSystems.newFileTypeDetectorsSupplier:(Ljava/lang/Iterable;)Ljava/util/function/Supplier;
            putfield com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext.fileTypeDetectors:Ljava/util/function/Supplier;
         4: .line 333
            return
        end local 0 // com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    5     0  this  Lcom/oracle/truffle/polyglot/PolyglotSource$EmbedderFileSystemContext;
}
SourceFile: "PolyglotSource.java"
NestHost: com.oracle.truffle.polyglot.PolyglotSource
InnerClasses:
  final EmbedderFileSystemContext = com.oracle.truffle.polyglot.PolyglotSource$EmbedderFileSystemContext of com.oracle.truffle.polyglot.PolyglotSource