@SuppressWarnings("unchecked")
  public static void copyFromProperties(Properties propSource, HiveConf confTarget) {
    Enumeration<String> props = (Enumeration<String>) propSource.propertyNames();
    while (props.hasMoreElements()) {
      String key = props.nextElement();
      confTarget.set(key, propSource.getProperty(key));
    }
  }
Sets a "keyName=newKeyValue" pair to a jobConf to a given property.
If the property is empty, it simply inserts keyName=newKeyValue,
if it's already filled, it takes care of appending or replacing it in the currently present value.
The property in jobConf contains a value like: "key1=value1,key2=value2".
@param jobConf
@param property
@param keyName
@param newKeyValue
common/src/java/org/apache/hadoop/hive/conf/HiveConfUtil.java