Program: 123394
Project: 123394
Buggy source:
private String addQuoteForSpecialChar(String expression,DbMapComponent component){
  List<String> specialList=new ArrayList<String>();
  List<IConnection> inputConnections=(List<IConnection>)component.getIncomingConnections();
  if (inputConnections == null) {
    return expression;
  }
  for (  IConnection iconn : inputConnections) {
    IMetadataTable metadataTable=iconn.getMetadataTable();
    List<IMetadataColumn> lColumn=metadataTable.getListColumns();
    for (    IMetadataColumn co : lColumn) {
      String columnLabel=co.getLabel();
      String exp=MetadataToolHelper.validateValueNoLengthLimit(columnLabel);
      if (!exp.equals(columnLabel)) {
        specialList.add(columnLabel);
      }
    }
  }
  for (  String specialColumn : specialList) {
    if (expression.contains(specialColumn)) {
      int begin=expression.indexOf(specialColumn);
      int length=specialColumn.length();
      int allLength=expression.length();
      expression=expression.substring(0,begin) + "String_Node_Str" + expression.substring(begin,begin + length)+ "String_Node_Str"+ expression.substring(begin + length,allLength);
      return expression;
    }
  }
  return expression;
}

Fixed version (ground truth):
private String addQuoteForSpecialChar(String expression,DbMapComponent component){
  List<String> specialList=new ArrayList<String>();
  Map<String,List<String>> map=new HashMap<String,List<String>>();
  List<IConnection> inputConnections=(List<IConnection>)component.getIncomingConnections();
  if (inputConnections == null) {
    return expression;
  }
  for (  IConnection iconn : inputConnections) {
    IMetadataTable metadataTable=iconn.getMetadataTable();
    List<IMetadataColumn> lColumn=metadataTable.getListColumns();
    for (    IMetadataColumn co : lColumn) {
      String columnLabel=co.getLabel();
      String exp=MetadataToolHelper.validateValueNoLengthLimit(columnLabel);
      if (!exp.equals(columnLabel)) {
        specialList.add(columnLabel);
      }
    }
  }
  for (  String specialColumn : specialList) {
    if (expression.contains(specialColumn)) {
      if (map.get(expression) == null) {
        List<String> list=new ArrayList<String>();
        list.add(specialColumn);
        map.put(expression,list);
      }
 else {
        List<String> list=map.get(expression);
        list.add(specialColumn);
      }
    }
  }
  if (map.size() > 0) {
    List<String> list=map.get(expression);
    for (int i=0; i < list.size() - 1; i++) {
      String first=list.get(i);
      String second=list.get(i + 1);
      String temp;
      if (first.length() > second.length()) {
        temp=first;
        first=second;
        second=temp;
      }
    }
    String specialColumn=list.get(list.size() - 1);
    if (expression.contains(specialColumn)) {
      int begin=expression.indexOf(specialColumn);
      int length=specialColumn.length();
      int allLength=expression.length();
      expression=expression.substring(0,begin) + "String_Node_Str" + expression.substring(begin,begin + length)+ "String_Node_Str"+ expression.substring(begin + length,allLength);
      return expression;
    }
  }
  return expression;
}