https://www.graalvm.org/ 
public class com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager
  super_class: java.lang.Object
{
  private static final java.util.Map<java.lang.Long, com.oracle.truffle.trufflenode.threading.JavaMessagePortData> activeMessagePortRefs;
    descriptor: Ljava/util/Map;
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    Signature: Ljava/util/Map<Ljava/lang/Long;Lcom/oracle/truffle/trufflenode/threading/JavaMessagePortData;>;

  static final boolean $assertionsDisabled;
    descriptor: Z
    flags: (0x1018) ACC_STATIC, ACC_FINAL, ACC_SYNTHETIC

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=0, args_size=0
         0: .line 53
            ldc Lcom/oracle/truffle/trufflenode/threading/SharedMemMessagingManager;
            invokevirtual java.lang.Class.desiredAssertionStatus:()Z
            ifne 1
            iconst_1
            goto 2
      StackMap locals:
      StackMap stack:
         1: iconst_0
      StackMap locals:
      StackMap stack: int
         2: putstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.$assertionsDisabled:Z
         3: .line 59
            new java.util.concurrent.ConcurrentHashMap
            dup
            invokespecial java.util.concurrent.ConcurrentHashMap.<init>:()V
            putstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.activeMessagePortRefs:Ljava/util/Map;
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager this
         0: .line 53
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/trufflenode/threading/SharedMemMessagingManager;

  public static com.oracle.truffle.trufflenode.threading.JavaMessagePortData getMessagePortDataFor(long);
    descriptor: (J)Lcom/oracle/truffle/trufflenode/threading/JavaMessagePortData;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=2, args_size=1
        start local 0 // long nativePointer
         0: .line 63
            getstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.$assertionsDisabled:Z
            ifne 1
            getstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.activeMessagePortRefs:Ljava/util/Map;
            lload 0 /* nativePointer */
            invokestatic java.lang.Long.valueOf:(J)Ljava/lang/Long;
            invokeinterface java.util.Map.containsKey:(Ljava/lang/Object;)Z
            ifne 1
            new java.lang.AssertionError
            dup
            invokespecial java.lang.AssertionError.<init>:()V
            athrow
         1: .line 64
      StackMap locals:
      StackMap stack:
            getstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.activeMessagePortRefs:Ljava/util/Map;
            lload 0 /* nativePointer */
            invokestatic java.lang.Long.valueOf:(J)Ljava/lang/Long;
            invokeinterface java.util.Map.get:(Ljava/lang/Object;)Ljava/lang/Object;
            checkcast com.oracle.truffle.trufflenode.threading.JavaMessagePortData
            areturn
        end local 0 // long nativePointer
      LocalVariableTable:
        Start  End  Slot           Name  Signature
            0    2     0  nativePointer  J
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.CompilerDirectives$TruffleBoundary()
    MethodParameters:
               Name  Flags
      nativePointer  

  public static com.oracle.truffle.trufflenode.threading.JavaMessagePortData getJavaMessagePortDataFor(com.oracle.truffle.trufflenode.JSExternalObject);
    descriptor: (Lcom/oracle/truffle/trufflenode/JSExternalObject;)Lcom/oracle/truffle/trufflenode/threading/JavaMessagePortData;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=4, args_size=1
        start local 0 // com.oracle.truffle.trufflenode.JSExternalObject nativeMessagePortData
         0: .line 69
            aload 0 /* nativeMessagePortData */
            invokevirtual com.oracle.truffle.trufflenode.JSExternalObject.getPointer:()J
            lstore 1 /* pointer */
        start local 1 // long pointer
         1: .line 71
            getstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.activeMessagePortRefs:Ljava/util/Map;
            lload 1 /* pointer */
            invokestatic java.lang.Long.valueOf:(J)Ljava/lang/Long;
            invokeinterface java.util.Map.get:(Ljava/lang/Object;)Ljava/lang/Object;
            checkcast com.oracle.truffle.trufflenode.threading.JavaMessagePortData
            astore 3 /* data */
        start local 3 // com.oracle.truffle.trufflenode.threading.JavaMessagePortData data
         2: .line 72
            aload 3 /* data */
            ifnonnull 5
         3: .line 73
            new com.oracle.truffle.trufflenode.threading.JavaMessagePortData
            dup
            aload 0 /* nativeMessagePortData */
            invokespecial com.oracle.truffle.trufflenode.threading.JavaMessagePortData.<init>:(Lcom/oracle/truffle/trufflenode/JSExternalObject;)V
            astore 3 /* data */
         4: .line 74
            getstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.activeMessagePortRefs:Ljava/util/Map;
            lload 1 /* pointer */
            invokestatic java.lang.Long.valueOf:(J)Ljava/lang/Long;
            aload 3 /* data */
            invokeinterface java.util.Map.put:(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
            pop
         5: .line 76
      StackMap locals: long com.oracle.truffle.trufflenode.threading.JavaMessagePortData
      StackMap stack:
            aload 3 /* data */
            areturn
        end local 3 // com.oracle.truffle.trufflenode.threading.JavaMessagePortData data
        end local 1 // long pointer
        end local 0 // com.oracle.truffle.trufflenode.JSExternalObject nativeMessagePortData
      LocalVariableTable:
        Start  End  Slot                   Name  Signature
            0    6     0  nativeMessagePortData  Lcom/oracle/truffle/trufflenode/JSExternalObject;
            1    6     1                pointer  J
            2    6     3                   data  Lcom/oracle/truffle/trufflenode/threading/JavaMessagePortData;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.CompilerDirectives$TruffleBoundary()
    MethodParameters:
                       Name  Flags
      nativeMessagePortData  

  public static void disposeReferences(com.oracle.truffle.trufflenode.JSExternalObject);
    descriptor: (Lcom/oracle/truffle/trufflenode/JSExternalObject;)V
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=3, args_size=1
        start local 0 // com.oracle.truffle.trufflenode.JSExternalObject nativeMessagePortData
         0: .line 81
            aload 0 /* nativeMessagePortData */
            invokevirtual com.oracle.truffle.trufflenode.JSExternalObject.getPointer:()J
            lstore 1 /* pointer */
        start local 1 // long pointer
         1: .line 82
            getstatic com.oracle.truffle.trufflenode.threading.SharedMemMessagingManager.activeMessagePortRefs:Ljava/util/Map;
            lload 1 /* pointer */
            invokestatic java.lang.Long.valueOf:(J)Ljava/lang/Long;
            invokeinterface java.util.Map.remove:(Ljava/lang/Object;)Ljava/lang/Object;
            pop
         2: .line 83
            return
        end local 1 // long pointer
        end local 0 // com.oracle.truffle.trufflenode.JSExternalObject nativeMessagePortData
      LocalVariableTable:
        Start  End  Slot                   Name  Signature
            0    3     0  nativeMessagePortData  Lcom/oracle/truffle/trufflenode/JSExternalObject;
            1    3     1                pointer  J
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.CompilerDirectives$TruffleBoundary()
    MethodParameters:
                       Name  Flags
      nativeMessagePortData  
}
SourceFile: "SharedMemMessagingManager.java"
InnerClasses:
  public abstract TruffleBoundary = com.oracle.truffle.api.CompilerDirectives$TruffleBoundary of com.oracle.truffle.api.CompilerDirectives