https://www.graalvm.org/ 
class com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry implements com.oracle.truffle.api.interop.TruffleObject
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry
  super_class: java.lang.Object
{
  private final java.util.Map<java.lang.String, java.lang.Object> functions;
    descriptor: Ljava/util/Map;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL
    Signature: Ljava/util/Map<Ljava/lang/String;Ljava/lang/Object;>;

  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
         0: .line 82
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 83
            aload 0 /* this */
            new java.util.HashMap
            dup
            invokespecial java.util.HashMap.<init>:()V
            putfield com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry.functions:Ljava/util/Map;
         2: .line 84
            return
        end local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.CompilerDirectives$TruffleBoundary()

  void clear();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
         0: .line 88
            aload 0 /* this */
            getfield com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry.functions:Ljava/util/Map;
            invokeinterface java.util.Map.clear:()V
         1: .line 89
            return
        end local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.CompilerDirectives$TruffleBoundary()

  void add(java.lang.String, java.lang.Object);
    descriptor: (Ljava/lang/String;Ljava/lang/Object;)V
    flags: (0x0000) 
    Code:
      stack=3, locals=3, args_size=3
        start local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
        start local 1 // java.lang.String name
        start local 2 // java.lang.Object function
         0: .line 93
            aload 0 /* this */
            getfield com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry.functions:Ljava/util/Map;
            aload 1 /* name */
            aload 2 /* function */
            invokeinterface java.util.Map.put:(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
            pop
         1: .line 94
            return
        end local 2 // java.lang.Object function
        end local 1 // java.lang.String name
        end local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    2     0      this  Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry;
            0    2     1      name  Ljava/lang/String;
            0    2     2  function  Ljava/lang/Object;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.CompilerDirectives$TruffleBoundary()
    MethodParameters:
          Name  Flags
      name      
      function  

  java.lang.Object get(java.lang.String);
    descriptor: (Ljava/lang/String;)Ljava/lang/Object;
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
        start local 1 // java.lang.String name
         0: .line 98
            aload 0 /* this */
            getfield com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry.functions:Ljava/util/Map;
            aload 1 /* name */
            invokeinterface java.util.Map.get:(Ljava/lang/Object;)Ljava/lang/Object;
            areturn
        end local 1 // java.lang.String name
        end local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry;
            0    1     1  name  Ljava/lang/String;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.CompilerDirectives$TruffleBoundary()
    MethodParameters:
      Name  Flags
      name  

  boolean isExecutable();
    descriptor: ()Z
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
         0: .line 103
            iconst_1
            ireturn
        end local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportMessage()

  java.lang.Object execute(java.lang.Object[], com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry$RegisterFunctionNode);
    descriptor: ([Ljava/lang/Object;Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry$RegisterFunctionNode;)Ljava/lang/Object;
    flags: (0x0000) 
    Code:
      stack=6, locals=3, args_size=3
        start local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
        start local 1 // java.lang.Object[] args
        start local 2 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry$RegisterFunctionNode register
         0: .line 109
            aload 2 /* register */
            aload 0 /* this */
            aload 1 /* args */
            iconst_0
            aaload
            checkcast java.lang.String
            aload 1 /* args */
            iconst_1
            aaload
            checkcast java.lang.String
            aload 1 /* args */
            iconst_2
            aaload
            invokevirtual com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry$RegisterFunctionNode.execute:(Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Object;)V
         1: .line 110
            ldc ""
            areturn
        end local 2 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry$RegisterFunctionNode register
        end local 1 // java.lang.Object[] args
        end local 0 // com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    2     0      this  Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry;
            0    2     1      args  [Ljava/lang/Object;
            0    2     2  register  Lcom/oracle/truffle/nfi/test/RegisterPackageNFITest$FunctionRegistry$RegisterFunctionNode;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportMessage()
    RuntimeInvisibleParameterAnnotations: 
      0:
      1:
        com.oracle.truffle.api.dsl.Cached()
    MethodParameters:
          Name  Flags
      args      
      register  
}
SourceFile: "RegisterPackageNFITest.java"
NestHost: com.oracle.truffle.nfi.test.RegisterPackageNFITest
InnerClasses:
  public abstract TruffleBoundary = com.oracle.truffle.api.CompilerDirectives$TruffleBoundary of com.oracle.truffle.api.CompilerDirectives
  FunctionRegistry = com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry of com.oracle.truffle.nfi.test.RegisterPackageNFITest
  abstract RegisterFunctionNode = com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry$RegisterFunctionNode of com.oracle.truffle.nfi.test.RegisterPackageNFITest$FunctionRegistry
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportLibrary(value = Lcom/oracle/truffle/api/interop/InteropLibrary;)