ClassAccess.java

import java.io.Serializable;
import java.util.EnumMap;
import java.util.Map;
import java.util.Set;

public class ClassAccess<caret> implements Serializable {

  enum TestEnum {}

  // at one point javac generated a synthetic field for .class accesses with a name starting with the string "class$"
  Map<TestEnum, Set<String>> testField = new EnumMap<TestEnum, Set<String>>(TestEnum.class);
  //    Map<TestEnum, Set<String>> testField = new HashMap<>();

}