Java Map のいくつかのループ メソッドの概要

for(String dataKey : paraMap.keySet())    
{    
    System.out.println(dataKey );               
}

for(Map.Entry<String, Object> entry : paraMap.entrySet())    
{    
    System.out.println(entry.getKey()+": "+entry.getValue());    
}

Iterator it = paraMap.entrySet().iterator();    
while (it.hasNext())     
{    
        Map.Entry pairs = (Map.Entry)it.next();    
        System.out.println(pairs.getKey() + " = " + pairs.getValue());    
 }