Program: 11328
Project: 11328
Buggy source:
private <T extends Item>Collection<T> executeQuery(final AttributeQuery query,final Class<T> itemClass){
  final Map<ItemId,T> allItems=getAllItems(itemClass);
  final Collection<T> matches=new ArrayList<>();
  for (  final T item : allItems.values()) {
    final String attribute=query.getAttributeName();
    try {
      final Method getter=new PropertyDescriptor(attribute,item.getClass()).getReadMethod();
      final Object itemPropertyValue=getter.invoke(item);
      final Class<?> itemPropertyType=getter.getReturnType();
      final Condition condition=query.getCondition();
      final Set<String> values=condition.getValues();
      if (Operators.NULL.equals(query.getCondition().getComparisonOperator())) {
        if (itemPropertyValue == null) {
          matches.add(item);
        }
      }
 else       if (Operators.NOT_NULL.equals(query.getCondition().getComparisonOperator())) {
        if (itemPropertyValue != null) {
          matches.add(item);
        }
      }
 else       if (String.class.isAssignableFrom(itemPropertyType) && values.size() == 1) {
        final String itemPropertyValueString=itemPropertyValue == null ? null : (String)itemPropertyValue;
        if (condition.getComparisonOperator().compare(itemPropertyValueString,values.iterator().next())) {
          matches.add(item);
        }
      }
 else       if (Collection.class.isAssignableFrom(itemPropertyType)) {
        @SuppressWarnings("String_Node_Str") final Collection<String> itemPropertyValueStringCollection=itemPropertyValue == null ? null : (Collection<String>)itemPropertyValue;
        if (condition.getComparisonOperator().compare(itemPropertyValueStringCollection,values)) {
          matches.add(item);
        }
      }
    }
 catch (    final Exception e) {
      throw new IllegalStateException("String_Node_Str" + attribute + "String_Node_Str"+ item.getClass()+ "String_Node_Str");
    }
  }
  return matches;
}

Fixed version (ground truth):
private <T extends Item>Collection<T> executeQuery(final AttributeQuery query,final Class<T> itemClass){
  final Map<ItemId,T> allItems=getAllItems(itemClass);
  final Collection<T> matches=new ArrayList<>();
  for (  final T item : allItems.values()) {
    final String attribute=query.getAttributeName();
    try {
      final Method getter=new PropertyDescriptor(attribute,item.getClass()).getReadMethod();
      final Object itemPropertyValue=getter.invoke(item);
      final Class<?> itemPropertyType=getter.getReturnType();
      final Condition condition=query.getCondition();
      final Set<String> values=condition.getValues();
      if (Operators.NULL.equals(query.getCondition().getComparisonOperator())) {
        if (itemPropertyValue == null) {
          matches.add(item);
        }
      }
 else       if (Operators.NOT_NULL.equals(query.getCondition().getComparisonOperator())) {
        if (itemPropertyValue != null) {
          matches.add(item);
        }
      }
 else       if (Collection.class.isAssignableFrom(itemPropertyType)) {
        @SuppressWarnings("String_Node_Str") final Collection<String> itemPropertyValueStringCollection=itemPropertyValue == null ? null : (Collection<String>)itemPropertyValue;
        if (condition.getComparisonOperator().compare(itemPropertyValueStringCollection,values)) {
          matches.add(item);
        }
      }
 else       if (values.size() == 1) {
        final String itemPropertyValueString=itemPropertyValue == null ? null : String.valueOf(itemPropertyValue);
        if (condition.getComparisonOperator().compare(itemPropertyValueString,values.iterator().next())) {
          matches.add(item);
        }
      }
    }
 catch (    final Exception e) {
      throw new IllegalStateException("String_Node_Str" + attribute + "String_Node_Str"+ item.getClass()+ "String_Node_Str");
    }
  }
  return matches;
}