map check if key not exists code example

Example 1: check if map contains key java

if (map.containsKey(key)) {
       // Okay, there's a key but the value is null
    } else {
       // Definitely no such key
    }

Example 2: check if a key is in a map

if ( m.find("f") == m.end() ) {
  // not found
} else {
  // found
}