Hashmap does not work with int, char [duplicate]

Answer 1

Generics can be defined using Wrapper classes only. If you don't want to define using Wrapper types, you may use the Raw definition as below

@SuppressWarnings("rawtypes")
public HashMap buildMap(String letters)
{
    HashMap checkSum = new HashMap();

    for ( int i = 0; i < letters.length(); ++i )
    {
       checkSum.put(letters.charAt(i), primes[i]);
    }
    return checkSum;
}

Or define the HashMap using wrapper types, and store the primitive types. The primitive values will be promoted to their wrapper types.

public HashMap<Character, Integer> buildMap(String letters)
{
  HashMap<Character, Integer> checkSum = new HashMap<Character, Integer>();

  for ( int i = 0; i < letters.length(); ++i )
  {
    checkSum.put(letters.charAt(i), primes[i]);
  }
  return checkSum;
}