https://www.graalvm.org/ 
public final class com.oracle.truffle.js.runtime.builtins.JSStringObject extends com.oracle.truffle.js.runtime.objects.JSNonProxyObject
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: com.oracle.truffle.js.runtime.builtins.JSStringObject
  super_class: com.oracle.truffle.js.runtime.objects.JSNonProxyObject
{
  private final java.lang.CharSequence string;
    descriptor: Ljava/lang/CharSequence;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  protected void <init>(com.oracle.truffle.api.object.Shape, java.lang.CharSequence);
    descriptor: (Lcom/oracle/truffle/api/object/Shape;Ljava/lang/CharSequence;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
        start local 1 // com.oracle.truffle.api.object.Shape shape
        start local 2 // java.lang.CharSequence string
         0: .line 56
            aload 0 /* this */
            aload 1 /* shape */
            invokespecial com.oracle.truffle.js.runtime.objects.JSNonProxyObject.<init>:(Lcom/oracle/truffle/api/object/Shape;)V
         1: .line 57
            aload 0 /* this */
            aload 2 /* string */
            putfield com.oracle.truffle.js.runtime.builtins.JSStringObject.string:Ljava/lang/CharSequence;
         2: .line 58
            return
        end local 2 // java.lang.CharSequence string
        end local 1 // com.oracle.truffle.api.object.Shape shape
        end local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    3     0    this  Lcom/oracle/truffle/js/runtime/builtins/JSStringObject;
            0    3     1   shape  Lcom/oracle/truffle/api/object/Shape;
            0    3     2  string  Ljava/lang/CharSequence;
    MethodParameters:
        Name  Flags
      shape   
      string  

  public java.lang.CharSequence getCharSequence();
    descriptor: ()Ljava/lang/CharSequence;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
         0: .line 61
            aload 0 /* this */
            getfield com.oracle.truffle.js.runtime.builtins.JSStringObject.string:Ljava/lang/CharSequence;
            areturn
        end local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/runtime/builtins/JSStringObject;

  public static com.oracle.truffle.api.object.DynamicObject create(com.oracle.truffle.api.object.Shape, java.lang.CharSequence);
    descriptor: (Lcom/oracle/truffle/api/object/Shape;Ljava/lang/CharSequence;)Lcom/oracle/truffle/api/object/DynamicObject;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=4, locals=2, args_size=2
        start local 0 // com.oracle.truffle.api.object.Shape shape
        start local 1 // java.lang.CharSequence value
         0: .line 65
            new com.oracle.truffle.js.runtime.builtins.JSStringObject
            dup
            aload 0 /* shape */
            aload 1 /* value */
            invokespecial com.oracle.truffle.js.runtime.builtins.JSStringObject.<init>:(Lcom/oracle/truffle/api/object/Shape;Ljava/lang/CharSequence;)V
            areturn
        end local 1 // java.lang.CharSequence value
        end local 0 // com.oracle.truffle.api.object.Shape shape
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    1     0  shape  Lcom/oracle/truffle/api/object/Shape;
            0    1     1  value  Ljava/lang/CharSequence;
    MethodParameters:
       Name  Flags
      shape  
      value  

  public static com.oracle.truffle.api.object.DynamicObject create(com.oracle.truffle.js.runtime.JSRealm, com.oracle.truffle.js.runtime.builtins.JSObjectFactory, java.lang.CharSequence);
    descriptor: (Lcom/oracle/truffle/js/runtime/JSRealm;Lcom/oracle/truffle/js/runtime/builtins/JSObjectFactory;Ljava/lang/CharSequence;)Lcom/oracle/truffle/api/object/DynamicObject;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=5, locals=3, args_size=3
        start local 0 // com.oracle.truffle.js.runtime.JSRealm realm
        start local 1 // com.oracle.truffle.js.runtime.builtins.JSObjectFactory factory
        start local 2 // java.lang.CharSequence value
         0: .line 69
            aload 1 /* factory */
            new com.oracle.truffle.js.runtime.builtins.JSStringObject
            dup
            aload 1 /* factory */
            aload 0 /* realm */
            invokevirtual com.oracle.truffle.js.runtime.builtins.JSObjectFactory.getShape:(Lcom/oracle/truffle/js/runtime/JSRealm;)Lcom/oracle/truffle/api/object/Shape;
            aload 2 /* value */
            invokespecial com.oracle.truffle.js.runtime.builtins.JSStringObject.<init>:(Lcom/oracle/truffle/api/object/Shape;Ljava/lang/CharSequence;)V
            aload 0 /* realm */
            invokevirtual com.oracle.truffle.js.runtime.builtins.JSObjectFactory.initProto:(Lcom/oracle/truffle/api/object/DynamicObject;Lcom/oracle/truffle/js/runtime/JSRealm;)Lcom/oracle/truffle/api/object/DynamicObject;
            areturn
        end local 2 // java.lang.CharSequence value
        end local 1 // com.oracle.truffle.js.runtime.builtins.JSObjectFactory factory
        end local 0 // com.oracle.truffle.js.runtime.JSRealm realm
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    1     0    realm  Lcom/oracle/truffle/js/runtime/JSRealm;
            0    1     1  factory  Lcom/oracle/truffle/js/runtime/builtins/JSObjectFactory;
            0    1     2    value  Ljava/lang/CharSequence;
    MethodParameters:
         Name  Flags
      realm    
      factory  
      value    

  public java.lang.String getClassName();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
         0: .line 74
            ldc "String"
            areturn
        end local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/runtime/builtins/JSStringObject;

  public boolean isString();
    descriptor: ()Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
         0: .line 80
            iconst_1
            ireturn
        end local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/runtime/builtins/JSStringObject;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportMessage()

  public java.lang.String asString();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
         0: .line 85
            aload 0 /* this */
            invokestatic com.oracle.truffle.js.runtime.builtins.JSString.getString:(Lcom/oracle/truffle/api/object/DynamicObject;)Ljava/lang/String;
            areturn
        end local 0 // com.oracle.truffle.js.runtime.builtins.JSStringObject this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/runtime/builtins/JSStringObject;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportMessage()
}
SourceFile: "JSStringObject.java"
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportLibrary(value = Lcom/oracle/truffle/api/interop/InteropLibrary;)