The Map interface in Java is implemented by the following classes:

1. HashMap: This class implements the Map interface and allows null values and the null key. It is not synchronized and maintains no order.

2. LinkedHashMap: This class is similar to HashMap but it maintains insertion order.

3. TreeMap: This class implements the Map interface and maintains ascending order. It is not synchronized and does not allow null keys but can have multiple null values.

4. Hashtable: This class is similar to HashMap but it is synchronized. It does not allow null keys or values.

5. Properties: This class is a subclass of Hashtable and represents a persistent set of properties. It can be used to store key-value pairs in the form of strings.

6. EnumMap: This class is a specialized Map implementation for use with enum type keys. All of the keys in an EnumMap must come from a single enum type that is specified when the map is created.

7. WeakHashMap: This class is an implementation of the Map interface that stores only weak references to its keys. This allows a key-value pair to be garbage-collected when the key is no longer referenced outside of the WeakHashMap.

Question

The Map interface in Java is implemented by the following classes:

1. HashMap: This class implements the Map interface and allows null values and the null key. It is not synchronized and maintains no order.

2. LinkedHashMap: This class is similar to HashMap but it maintains insertion order.

3. TreeMap: This class implements the Map interface and maintains ascending order. It is not synchronized and does not allow null keys but can have multiple null values.

4. Hashtable: This class is similar to HashMap but it is synchronized. It does not allow null keys or values.

5. Properties: This class is a subclass of Hashtable and represents a persistent set of properties. It can be used to store key-value pairs in the form of strings.

6. EnumMap: This class is a specialized Map implementation for use with enum type keys. All of the keys in an EnumMap must come from a single enum type that is specified when the map is created.

7. WeakHashMap: This class is an implementation of the Map interface that stores only weak references to its keys. This allows a key-value pair to be garbage-collected when the key is no longer referenced outside of the WeakHashMap.

Knowee AI · Accepted Answer