https://www.graalvm.org/ 
class com.oracle.truffle.trufflenode.buffer.NIOBuffer$1 extends com.oracle.truffle.js.runtime.JavaScriptRootNode
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.trufflenode.buffer.NIOBuffer$1
  super_class: com.oracle.truffle.js.runtime.JavaScriptRootNode
{
  private final com.oracle.truffle.js.runtime.JSContext val$context;
    descriptor: Lcom/oracle/truffle/js/runtime/JSContext;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.oracle.truffle.js.runtime.JSContext);
    descriptor: (Lcom/oracle/truffle/js/runtime/JSContext;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.oracle.truffle.trufflenode.buffer.NIOBuffer$1 this
         0: .line 87
            aload 0 /* this */
            aload 1
            putfield com.oracle.truffle.trufflenode.buffer.NIOBuffer$1.val$context:Lcom/oracle/truffle/js/runtime/JSContext;
            aload 0 /* this */
            invokespecial com.oracle.truffle.js.runtime.JavaScriptRootNode.<init>:()V
            return
        end local 0 // com.oracle.truffle.trufflenode.buffer.NIOBuffer$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/trufflenode/buffer/NIOBuffer$1;
    MethodParameters:
             Name  Flags
      val$context  final

  public java.lang.Object execute(com.oracle.truffle.api.frame.VirtualFrame);
    descriptor: (Lcom/oracle/truffle/api/frame/VirtualFrame;)Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=6, args_size=2
        start local 0 // com.oracle.truffle.trufflenode.buffer.NIOBuffer$1 this
        start local 1 // com.oracle.truffle.api.frame.VirtualFrame frame
         0: .line 90
            aload 1 /* frame */
            invokeinterface com.oracle.truffle.api.frame.VirtualFrame.getArguments:()[Ljava/lang/Object;
            astore 2 /* args */
        start local 2 // java.lang.Object[] args
         1: .line 91
            getstatic com.oracle.truffle.trufflenode.buffer.NIOBuffer.$assertionsDisabled:Z
            ifne 2
            aload 2 /* args */
            arraylength
            iconst_4
            if_icmpeq 2
            new java.lang.AssertionError
            dup
            invokespecial java.lang.AssertionError.<init>:()V
            athrow
         2: .line 92
      StackMap locals: java.lang.Object[]
      StackMap stack:
            aload 2 /* args */
            iconst_2
            aaload
            checkcast com.oracle.truffle.api.object.DynamicObject
            astore 3 /* nativeUtf8Write */
        start local 3 // com.oracle.truffle.api.object.DynamicObject nativeUtf8Write
         3: .line 93
            aload 2 /* args */
            iconst_3
            aaload
            checkcast com.oracle.truffle.api.object.DynamicObject
            astore 4 /* nativeUtf8Slice */
        start local 4 // com.oracle.truffle.api.object.DynamicObject nativeUtf8Slice
         4: .line 94
            aload 0 /* this */
            getfield com.oracle.truffle.trufflenode.buffer.NIOBuffer$1.val$context:Lcom/oracle/truffle/js/runtime/JSContext;
            invokevirtual com.oracle.truffle.js.runtime.JSContext.getRealm:()Lcom/oracle/truffle/js/runtime/JSRealm;
            invokestatic com.oracle.truffle.trufflenode.GraalJSAccess.getRealmEmbedderData:(Ljava/lang/Object;)Lcom/oracle/truffle/trufflenode/RealmData;
            astore 5 /* embedderData */
        start local 5 // com.oracle.truffle.trufflenode.RealmData embedderData
         5: .line 95
            aload 5 /* embedderData */
            aload 3 /* nativeUtf8Write */
            invokevirtual com.oracle.truffle.trufflenode.RealmData.setNativeUtf8Write:(Lcom/oracle/truffle/api/object/DynamicObject;)V
         6: .line 96
            aload 5 /* embedderData */
            aload 4 /* nativeUtf8Slice */
            invokevirtual com.oracle.truffle.trufflenode.RealmData.setNativeUtf8Slice:(Lcom/oracle/truffle/api/object/DynamicObject;)V
         7: .line 97
            aload 0 /* this */
            getfield com.oracle.truffle.trufflenode.buffer.NIOBuffer$1.val$context:Lcom/oracle/truffle/js/runtime/JSContext;
            invokestatic com.oracle.truffle.trufflenode.buffer.NIOBuffer.create:(Lcom/oracle/truffle/js/runtime/JSContext;)Lcom/oracle/truffle/api/object/DynamicObject;
            areturn
        end local 5 // com.oracle.truffle.trufflenode.RealmData embedderData
        end local 4 // com.oracle.truffle.api.object.DynamicObject nativeUtf8Slice
        end local 3 // com.oracle.truffle.api.object.DynamicObject nativeUtf8Write
        end local 2 // java.lang.Object[] args
        end local 1 // com.oracle.truffle.api.frame.VirtualFrame frame
        end local 0 // com.oracle.truffle.trufflenode.buffer.NIOBuffer$1 this
      LocalVariableTable:
        Start  End  Slot             Name  Signature
            0    8     0             this  Lcom/oracle/truffle/trufflenode/buffer/NIOBuffer$1;
            0    8     1            frame  Lcom/oracle/truffle/api/frame/VirtualFrame;
            1    8     2             args  [Ljava/lang/Object;
            3    8     3  nativeUtf8Write  Lcom/oracle/truffle/api/object/DynamicObject;
            4    8     4  nativeUtf8Slice  Lcom/oracle/truffle/api/object/DynamicObject;
            5    8     5     embedderData  Lcom/oracle/truffle/trufflenode/RealmData;
    MethodParameters:
       Name  Flags
      frame  
}
SourceFile: "NIOBuffer.java"
EnclosingMethod: com.oracle.truffle.trufflenode.buffer.NIOBuffer.createInitFunction:(Lcom/oracle/truffle/js/runtime/JSContext;)Ljava/lang/Object;
NestHost: com.oracle.truffle.trufflenode.buffer.NIOBuffer
InnerClasses:
  com.oracle.truffle.trufflenode.buffer.NIOBuffer$1