Hash map kotlin and java signature

hashmap_signature.kt

// Kotlin signature
typealias HashMap<K, V> = HashMap<K, V>
// Java signature
class HashMap<K,V> 
  extends AbstractMap<K,V> 
  implements Map<K,V>, Cloneable, Serializable
// AbstractMap<K,V> is a skeletal implementation of the Map interface,
// Java's Map<K,V> is very close to MutableMap<K,V> than kotlin's Map<K,V>
// i.e it contains mutable opertaions internally, though use structures named 
// similar to Kotlin's Map<K,V> like Map.Entry but are infact Mutable Entry
Java HashMap has three constructors
 - HashMap() 
 - HashMap(int initialCapacity)
 - HashMap(int initialCapacity,float fillRatio)
 - HashMap(Map<K,V> fromMap)