https://www.graalvm.org/ 
public interface com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer extends com.oracle.truffle.js.runtime.builtins.JSFunctionData$Initializer
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer
  super_class: java.lang.Object
{
  public static final boolean $assertionsDisabled;
    descriptor: Z
    flags: (0x1019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL, ACC_SYNTHETIC

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=1, locals=0, args_size=0
         0: .line 425
            ldc Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;
            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.js.runtime.builtins.JSFunctionData$CallTargetInitializer.$assertionsDisabled:Z
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  public abstract void initializeCallTarget(com.oracle.truffle.js.runtime.builtins.JSFunctionData, com.oracle.truffle.js.runtime.builtins.JSFunctionData$Target, com.oracle.truffle.api.CallTarget);
    descriptor: (Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$Target;Lcom/oracle/truffle/api/CallTarget;)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
              Name  Flags
      functionData  
      target        
      rootTarget    

  public void initializeEager(com.oracle.truffle.js.runtime.builtins.JSFunctionData);
    descriptor: (Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=4, locals=3, args_size=2
        start local 0 // com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer this
        start local 1 // com.oracle.truffle.js.runtime.builtins.JSFunctionData functionData
         0: .line 429
            getstatic com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer.$assertionsDisabled:Z
            ifne 1
            aload 1 /* functionData */
            getfield com.oracle.truffle.js.runtime.builtins.JSFunctionData.rootTarget:Lcom/oracle/truffle/api/CallTarget;
            ifnull 1
            new java.lang.AssertionError
            dup
            invokespecial java.lang.AssertionError.<init>:()V
            athrow
         1: .line 430
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 1 /* functionData */
            invokeinterface com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer.initializeRoot:(Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;)V
         2: .line 431
            aload 1 /* functionData */
            getfield com.oracle.truffle.js.runtime.builtins.JSFunctionData.rootTarget:Lcom/oracle/truffle/api/CallTarget;
            invokestatic java.util.Objects.requireNonNull:(Ljava/lang/Object;)Ljava/lang/Object;
            checkcast com.oracle.truffle.api.CallTarget
            astore 2 /* rootTarget */
        start local 2 // com.oracle.truffle.api.CallTarget rootTarget
         3: .line 432
            aload 0 /* this */
            aload 1 /* functionData */
            getstatic com.oracle.truffle.js.runtime.builtins.JSFunctionData$Target.Call:Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$Target;
            aload 2 /* rootTarget */
            invokeinterface com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer.initializeCallTarget:(Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$Target;Lcom/oracle/truffle/api/CallTarget;)V
         4: .line 433
            aload 0 /* this */
            aload 1 /* functionData */
            getstatic com.oracle.truffle.js.runtime.builtins.JSFunctionData$Target.Construct:Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$Target;
            aload 2 /* rootTarget */
            invokeinterface com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer.initializeCallTarget:(Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$Target;Lcom/oracle/truffle/api/CallTarget;)V
         5: .line 434
            aload 0 /* this */
            aload 1 /* functionData */
            getstatic com.oracle.truffle.js.runtime.builtins.JSFunctionData$Target.ConstructNewTarget:Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$Target;
            aload 2 /* rootTarget */
            invokeinterface com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer.initializeCallTarget:(Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$Target;Lcom/oracle/truffle/api/CallTarget;)V
         6: .line 435
            return
        end local 2 // com.oracle.truffle.api.CallTarget rootTarget
        end local 1 // com.oracle.truffle.js.runtime.builtins.JSFunctionData functionData
        end local 0 // com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer this
      LocalVariableTable:
        Start  End  Slot          Name  Signature
            0    7     0          this  Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData$CallTargetInitializer;
            0    7     1  functionData  Lcom/oracle/truffle/js/runtime/builtins/JSFunctionData;
            3    7     2    rootTarget  Lcom/oracle/truffle/api/CallTarget;
    MethodParameters:
              Name  Flags
      functionData  
}
SourceFile: "JSFunctionData.java"
NestHost: com.oracle.truffle.js.runtime.builtins.JSFunctionData
InnerClasses:
  public abstract CallTargetInitializer = com.oracle.truffle.js.runtime.builtins.JSFunctionData$CallTargetInitializer of com.oracle.truffle.js.runtime.builtins.JSFunctionData
  public abstract Initializer = com.oracle.truffle.js.runtime.builtins.JSFunctionData$Initializer of com.oracle.truffle.js.runtime.builtins.JSFunctionData
  public final Target = com.oracle.truffle.js.runtime.builtins.JSFunctionData$Target of com.oracle.truffle.js.runtime.builtins.JSFunctionData