Program: 78204
Project: 78204
Buggy source:
@Override public Object getClient(List list,String balanceKey){
  if (list.size() == 0) {
    return null;
  }
  if (null == balanceKey) {
    return super.getClient(list,null);
  }
  Object client=taskTable.get(balanceKey);
  Set listSet=new HashSet(list);
  Set taskTableSet=new HashSet();
  if (taskTable.values().isEmpty()) {
    taskTableSet=new HashSet();
  }
  if (null == client) {
    Set taskTableWidhout=Sets.difference(listSet,taskTableSet);
    if (!taskTableWidhout.isEmpty()) {
      taskTable.put(balanceKey,taskTableWidhout.iterator().next());
    }
 else {
      Map<Object,Integer> groupClientCount=new HashMap<Object,Integer>();
      for (      Map.Entry<String,Object> element : taskTable.entrySet()) {
        Object clientObj=element.getValue();
        if (null == groupClientCount.get(clientObj)) {
          groupClientCount.put(clientObj,1);
        }
 else {
          int tmp=groupClientCount.get(clientObj);
          groupClientCount.put(clientObj,++tmp);
        }
      }
      Object res=null;
      Integer minCount=0;
      for (      Map.Entry<Object,Integer> element : groupClientCount.entrySet()) {
        Object key=element.getKey();
        Integer value=element.getValue();
        if (null == res || minCount < value) {
          res=key;
          minCount=value;
        }
      }
      taskTable.put(balanceKey,res);
    }
    client=taskTable.get(balanceKey);
  }
  Set listWidhout=Sets.difference(taskTableSet,listSet);
  for (  Object object : listWidhout) {
    String removeKey=null;
    for (    Map.Entry<String,Object> element : taskTable.entrySet()) {
      if (element.getValue() == object) {
        removeKey=element.getKey();
        break;
      }
    }
    taskTable.remove(removeKey);
  }
  return client;
}

Fixed version (ground truth):
@Override public Object getClient(List list,String balanceKey){
  if (list.size() == 0) {
    return null;
  }
  if (null == balanceKey) {
    return super.getClient(list,null);
  }
  Object client=taskTable.get(balanceKey);
  Set listSet=new HashSet(list);
  Collection<Object> taskSets=taskTable.values();
  Set taskTableSet=Sets.newHashSet(taskSets);
  if (null == taskTableSet || taskTableSet.isEmpty()) {
    taskTableSet=new HashSet();
  }
  if (null == client) {
    Set taskTableWidhout=Sets.difference(listSet,taskTableSet);
    if (!taskTableWidhout.isEmpty()) {
      taskTable.put(balanceKey,taskTableWidhout.iterator().next());
    }
 else {
      Map<Object,Integer> groupClientCount=new HashMap<Object,Integer>();
      for (      Map.Entry<String,Object> element : taskTable.entrySet()) {
        Object clientObj=element.getValue();
        if (null == groupClientCount.get(clientObj)) {
          groupClientCount.put(clientObj,1);
        }
 else {
          int tmp=groupClientCount.get(clientObj);
          groupClientCount.put(clientObj,++tmp);
        }
      }
      Object res=null;
      Integer minCount=0;
      for (      Map.Entry<Object,Integer> element : groupClientCount.entrySet()) {
        Object key=element.getKey();
        Integer value=element.getValue();
        if (null == res || minCount < value) {
          res=key;
          minCount=value;
        }
      }
      taskTable.put(balanceKey,res);
    }
    client=taskTable.get(balanceKey);
  }
  Set listWidhout=Sets.difference(taskTableSet,listSet);
  for (  Object object : listWidhout) {
    String removeKey=null;
    for (    Map.Entry<String,Object> element : taskTable.entrySet()) {
      if (element.getValue() == object) {
        removeKey=element.getKey();
        break;
      }
    }
    taskTable.remove(removeKey);
  }
  return client;
}