java-map.md

Maps

Methods

computeIfAbsent

private Map<String, Object01> myMap = new HashMap<>();
myMap.computeIfAbsent("key01", this::method01);

• computeIfAbsent will call method01 if key key01 is not present in the map or if it is null.
• Above method method01 can accept the key value as parameter

private Object01 method01(String key) {
  // do something ...
  return object01;
}