https://openjdk.java.net/ 
public interface org.graalvm.compiler.core.common.Fields$ObjectTransformer
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: org.graalvm.compiler.core.common.Fields$ObjectTransformer
  super_class: java.lang.Object
{
  public abstract java.lang.Object apply(int, java.lang.Object);
    descriptor: (ILjava/lang/Object;)Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
       Name  Flags
      index  
      from   
}
SourceFile: "Fields.java"
NestHost: org.graalvm.compiler.core.common.Fields
InnerClasses:
  public abstract ObjectTransformer = org.graalvm.compiler.core.common.Fields$ObjectTransformer of org.graalvm.compiler.core.common.Fields
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()