### Question:
FieldName implements Serializable { static FieldName unmarshal(String value){ FieldName name = new FieldName(value); WeakReference<FieldName> reference = FieldName.cache.get(name); if(reference != null){ FieldName cachedName = reference.get(); if(cachedName != null){ return cachedName; } } FieldName.cache.put(name, new WeakReference<FieldName>(name)); return name; } FieldName(String value); FieldName intern(); @Override int hashCode(); @Override boolean equals(Object object); @Override String toString(); String getValue(); static FieldName create(String value);  }### Answer:
@Test public void unmarshal(){ assertNotNull(FieldName.unmarshal("x")); }