Summary of Classes and Interfaces - Absolute Java - page 1166

HashMap<K,V> Class
Package: java.util
Ancestor classes:
Object
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+--AbstractMap<K,V>
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+--HashMap<K,V>
Implements interfaces: Map<K,V> , Cloneable , Serializable
The HashMap<K,V> class implements all of the methods in the Map<K,V> interface. The only
other methods in the HashMap<K,V> class are the constructors.
All the exception classes mentioned are the kind that are not required to be caught in a catch
block or declared in a throws clause. All the exception classes mentioned are in the package
java.lang and so do not require any import statement. The class K must implement the
equals and hashCode methods.
public HashMap()
Creates a new, empty map with a default initial capacity of 16 and load factor of 0.75. The
capacity is the number of slots in the hash table. The load factor is the percentage of capacity
before the size of the table is automatically increased.
public HashMap( int initialCapacity)
Creates a new, empty map with a default capacity of initialCapacity and load factor of 0.75.
Throws:
IllegalArgumentException if the initial capacity is negative.
public HashMap( int initialCapacity, float loadFactor)
Creates a new, empty map with the specifi ed capacity and load factor.
Throws:
IllegalArgumentException if the initial capacity or the load factor is negative.
public HashMap(Map<? extends K,? extends V> m)
Creates a new map with the same mappings as m . The initialCapacity is set to the same
size as m and the loadFactor to 0.75.
Throws:
NullPointerException if m is null .
public Object clone( )
Creates a shallow copy of this instance and returns it. The keys and values are not cloned.
The remainder of the methods are the same as those described for the Map<K,V> interface.