https://www.graalvm.org/ 
public final class com.oracle.truffle.js.runtime.JSEngine
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: com.oracle.truffle.js.runtime.JSEngine
  super_class: java.lang.Object
{
  private static final com.oracle.truffle.js.runtime.JSEngine INSTANCE;
    descriptor: Lcom/oracle/truffle/js/runtime/JSEngine;
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL

  private final com.oracle.truffle.js.runtime.Evaluator parser;
    descriptor: Lcom/oracle/truffle/js/runtime/Evaluator;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=0, args_size=0
         0: .line 49
            new com.oracle.truffle.js.runtime.JSEngine
            dup
            invokespecial com.oracle.truffle.js.runtime.JSEngine.<init>:()V
            putstatic com.oracle.truffle.js.runtime.JSEngine.INSTANCE:Lcom/oracle/truffle/js/runtime/JSEngine;
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=3, locals=2, args_size=1
        start local 0 // com.oracle.truffle.js.runtime.JSEngine this
         0: .line 53
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 54
            aload 0 /* this */
            invokevirtual java.lang.Object.getClass:()Ljava/lang/Class;
            invokevirtual java.lang.Class.getClassLoader:()Ljava/lang/ClassLoader;
            astore 1 /* classLoader */
        start local 1 // java.lang.ClassLoader classLoader
         2: .line 55
            aload 0 /* this */
            ldc Lcom/oracle/truffle/js/runtime/Evaluator;
            aload 1 /* classLoader */
            invokestatic java.util.ServiceLoader.load:(Ljava/lang/Class;Ljava/lang/ClassLoader;)Ljava/util/ServiceLoader;
            invokevirtual java.util.ServiceLoader.iterator:()Ljava/util/Iterator;
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast com.oracle.truffle.js.runtime.Evaluator
            putfield com.oracle.truffle.js.runtime.JSEngine.parser:Lcom/oracle/truffle/js/runtime/Evaluator;
         3: .line 56
            return
        end local 1 // java.lang.ClassLoader classLoader
        end local 0 // com.oracle.truffle.js.runtime.JSEngine this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0    4     0         this  Lcom/oracle/truffle/js/runtime/JSEngine;
            2    4     1  classLoader  Ljava/lang/ClassLoader;

  public static com.oracle.truffle.js.runtime.JSEngine getInstance();
    descriptor: ()Lcom/oracle/truffle/js/runtime/JSEngine;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=1, locals=0, args_size=0
         0: .line 59
            getstatic com.oracle.truffle.js.runtime.JSEngine.INSTANCE:Lcom/oracle/truffle/js/runtime/JSEngine;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  public com.oracle.truffle.js.runtime.Evaluator getEvaluator();
    descriptor: ()Lcom/oracle/truffle/js/runtime/Evaluator;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.js.runtime.JSEngine this
         0: .line 63
            aload 0 /* this */
            getfield com.oracle.truffle.js.runtime.JSEngine.parser:Lcom/oracle/truffle/js/runtime/Evaluator;
            areturn
        end local 0 // com.oracle.truffle.js.runtime.JSEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/runtime/JSEngine;

  public com.oracle.truffle.js.runtime.Evaluator getParser();
    descriptor: ()Lcom/oracle/truffle/js/runtime/Evaluator;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.js.runtime.JSEngine this
         0: .line 67
            aload 0 /* this */
            getfield com.oracle.truffle.js.runtime.JSEngine.parser:Lcom/oracle/truffle/js/runtime/Evaluator;
            areturn
        end local 0 // com.oracle.truffle.js.runtime.JSEngine this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/runtime/JSEngine;

  private com.oracle.truffle.js.runtime.JSContext createContext(com.oracle.truffle.js.lang.JavaScriptLanguage, com.oracle.truffle.api.TruffleLanguage$Env);
    descriptor: (Lcom/oracle/truffle/js/lang/JavaScriptLanguage;Lcom/oracle/truffle/api/TruffleLanguage$Env;)Lcom/oracle/truffle/js/runtime/JSContext;
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=4, locals=4, args_size=3
        start local 0 // com.oracle.truffle.js.runtime.JSEngine this
        start local 1 // com.oracle.truffle.js.lang.JavaScriptLanguage language
        start local 2 // com.oracle.truffle.api.TruffleLanguage$Env env
         0: .line 71
            aload 2 /* env */
            invokevirtual com.oracle.truffle.api.TruffleLanguage$Env.getOptions:()Lorg/graalvm/options/OptionValues;
            invokestatic com.oracle.truffle.js.runtime.JSContextOptions.fromOptionValues:(Lorg/graalvm/options/OptionValues;)Lcom/oracle/truffle/js/runtime/JSContextOptions;
            astore 3 /* contextOptions */
        start local 3 // com.oracle.truffle.js.runtime.JSContextOptions contextOptions
         1: .line 72
            aload 0 /* this */
            getfield com.oracle.truffle.js.runtime.JSEngine.parser:Lcom/oracle/truffle/js/runtime/Evaluator;
            aload 3 /* contextOptions */
            aload 1 /* language */
            aload 2 /* env */
            invokestatic com.oracle.truffle.js.runtime.JSContext.createContext:(Lcom/oracle/truffle/js/runtime/Evaluator;Lcom/oracle/truffle/js/runtime/JSContextOptions;Lcom/oracle/truffle/js/lang/JavaScriptLanguage;Lcom/oracle/truffle/api/TruffleLanguage$Env;)Lcom/oracle/truffle/js/runtime/JSContext;
            areturn
        end local 3 // com.oracle.truffle.js.runtime.JSContextOptions contextOptions
        end local 2 // com.oracle.truffle.api.TruffleLanguage$Env env
        end local 1 // com.oracle.truffle.js.lang.JavaScriptLanguage language
        end local 0 // com.oracle.truffle.js.runtime.JSEngine this
      LocalVariableTable:
        Start  End  Slot            Name  Signature
            0    2     0            this  Lcom/oracle/truffle/js/runtime/JSEngine;
            0    2     1        language  Lcom/oracle/truffle/js/lang/JavaScriptLanguage;
            0    2     2             env  Lcom/oracle/truffle/api/TruffleLanguage$Env;
            1    2     3  contextOptions  Lcom/oracle/truffle/js/runtime/JSContextOptions;
    MethodParameters:
          Name  Flags
      language  
      env       

  public com.oracle.truffle.js.runtime.JSContext createContext(com.oracle.truffle.js.lang.JavaScriptLanguage, com.oracle.truffle.js.runtime.JSContextOptions, com.oracle.truffle.api.TruffleLanguage$Env);
    descriptor: (Lcom/oracle/truffle/js/lang/JavaScriptLanguage;Lcom/oracle/truffle/js/runtime/JSContextOptions;Lcom/oracle/truffle/api/TruffleLanguage$Env;)Lcom/oracle/truffle/js/runtime/JSContext;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=4, locals=4, args_size=4
        start local 0 // com.oracle.truffle.js.runtime.JSEngine this
        start local 1 // com.oracle.truffle.js.lang.JavaScriptLanguage language
        start local 2 // com.oracle.truffle.js.runtime.JSContextOptions contextOptions
        start local 3 // com.oracle.truffle.api.TruffleLanguage$Env env
         0: .line 76
            aload 0 /* this */
            getfield com.oracle.truffle.js.runtime.JSEngine.parser:Lcom/oracle/truffle/js/runtime/Evaluator;
            aload 2 /* contextOptions */
            aload 1 /* language */
            aload 3 /* env */
            invokestatic com.oracle.truffle.js.runtime.JSContext.createContext:(Lcom/oracle/truffle/js/runtime/Evaluator;Lcom/oracle/truffle/js/runtime/JSContextOptions;Lcom/oracle/truffle/js/lang/JavaScriptLanguage;Lcom/oracle/truffle/api/TruffleLanguage$Env;)Lcom/oracle/truffle/js/runtime/JSContext;
            areturn
        end local 3 // com.oracle.truffle.api.TruffleLanguage$Env env
        end local 2 // com.oracle.truffle.js.runtime.JSContextOptions contextOptions
        end local 1 // com.oracle.truffle.js.lang.JavaScriptLanguage language
        end local 0 // com.oracle.truffle.js.runtime.JSEngine this
      LocalVariableTable:
        Start  End  Slot            Name  Signature
            0    1     0            this  Lcom/oracle/truffle/js/runtime/JSEngine;
            0    1     1        language  Lcom/oracle/truffle/js/lang/JavaScriptLanguage;
            0    1     2  contextOptions  Lcom/oracle/truffle/js/runtime/JSContextOptions;
            0    1     3             env  Lcom/oracle/truffle/api/TruffleLanguage$Env;
    MethodParameters:
                Name  Flags
      language        
      contextOptions  
      env             

  public static com.oracle.truffle.js.runtime.JSContext createJSContext(com.oracle.truffle.js.lang.JavaScriptLanguage, com.oracle.truffle.api.TruffleLanguage$Env);
    descriptor: (Lcom/oracle/truffle/js/lang/JavaScriptLanguage;Lcom/oracle/truffle/api/TruffleLanguage$Env;)Lcom/oracle/truffle/js/runtime/JSContext;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.oracle.truffle.js.lang.JavaScriptLanguage language
        start local 1 // com.oracle.truffle.api.TruffleLanguage$Env env
         0: .line 80
            invokestatic com.oracle.truffle.js.runtime.JSEngine.getInstance:()Lcom/oracle/truffle/js/runtime/JSEngine;
            aload 0 /* language */
            aload 1 /* env */
            invokevirtual com.oracle.truffle.js.runtime.JSEngine.createContext:(Lcom/oracle/truffle/js/lang/JavaScriptLanguage;Lcom/oracle/truffle/api/TruffleLanguage$Env;)Lcom/oracle/truffle/js/runtime/JSContext;
            areturn
        end local 1 // com.oracle.truffle.api.TruffleLanguage$Env env
        end local 0 // com.oracle.truffle.js.lang.JavaScriptLanguage language
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    1     0  language  Lcom/oracle/truffle/js/lang/JavaScriptLanguage;
            0    1     1       env  Lcom/oracle/truffle/api/TruffleLanguage$Env;
    MethodParameters:
          Name  Flags
      language  
      env       
}
SourceFile: "JSEngine.java"
InnerClasses:
  public final Env = com.oracle.truffle.api.TruffleLanguage$Env of com.oracle.truffle.api.TruffleLanguage