When only the keys from a map are needed in a loop, iterating the keySet
makes sense. But when both the key and the value are needed, it's more efficient to iterate the entrySet
, which will give access to both the key and value, instead.
Noncompliant Code Example
public void doSomethingWithMap(Map<String,Object> map) { for (String key : map.keySet()) { // Noncompliant; for each key the value is retrieved Object value = map.get(key); // ... } }
Compliant Solution
public void doSomethingWithMap(Map<String,Object> map) { for (Map.Entry<String,Object> entry : map.entrySet()) { String key = entry.getKey(); Object value = entry.getValue(); // ... } }