public SimpleImmutableEntry(Entry<? extends K, ? extends V> entry) 
{
            this.key   = entry.getKey();
            this.value = entry.getValue();
}

Creates an entry representing the same mapping as the specified entry.

Parameters:

entry - the entry to copy

 public SimpleImmutableEntry(K key,
    V value) 
{
            this.key   = key;
            this.value = value;
}

Creates an entry representing a mapping from the specified key to the specified value.

Parameters:

key - the key represented by this entry

value - the value represented by this entry

 public boolean equals(Object o) 
{
            if (!(o instanceof Map.Entry))
                return false;
            Map.Entry e = (Map.Entry)o;
            return eq(key, e.getKey()) && eq(value, e.getValue());
}

Compares the specified object with this entry for equality. Returns {@code true} if the given object is also a map entry and the two entries represent the same mapping. More formally, two entries {@code e1} and {@code e2} represent the same mapping if

  (e1.getKey()==null ?
   e2.getKey()==null :
   e1.getKey().equals(e2.getKey()))
  &&
  (e1.getValue()==null ?
   e2.getValue()==null :
   e1.getValue().equals(e2.getValue()))

This ensures that the {@code equals} method works properly across different implementations of the {@code Map.Entry} interface.

 public K getKey() 
{
            return key;
}

Returns the key corresponding to this entry.

 public V getValue() 
{
            return value;
}

Returns the value corresponding to this entry.

 public int hashCode() 
{
            return (key   == null ? 0 :   key.hashCode()) ^
                   (value == null ? 0 : value.hashCode());
}

Returns the hash code value for this map entry. The hash code of a map entry {@code e} is defined to be:

  (e.getKey()==null   ? 0 : e.getKey().hashCode()) ^
  (e.getValue()==null ? 0 : e.getValue().hashCode())

This ensures that {@code e1.equals(e2)} implies that {@code e1.hashCode()==e2.hashCode()} for any two Entries {@code e1} and {@code e2}, as required by the general contract of Object#hashCode .

 public V setValue(V value) 
{
            throw new UnsupportedOperationException();
}

Replaces the value corresponding to this entry with the specified value (optional operation). This implementation simply throws UnsupportedOperationException, as this class implements an immutable map entry.

 public String toString() 
{
            return key + "=" + value;
}

Returns a String representation of this map entry. This implementation returns the string representation of this entry's key followed by the equals character ("=") followed by the string representation of this entry's value.