Map interface in java - Theory - Explained in Detail
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Map interface in Java:-
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1. Map is an interface which is available java.util package.
2. Map concept is used to represent the data in the form of key-value pair.
3. It was in the JDK1.2 version.
4. Please be informed that the keys must be unique and the values can be duplicated.
5. Map is going to all the unique keys , but the values can be duplicated.
6. By default, the Map does not follow the insertion order.
7. By default, the Map does not follow the sorting order.
8. By default, Heterogeneous elements are allowed at both keys and values.
9. Keys are able to allow only one null value , but the values, they allow any number of null values.
Methods in Maps:-
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1. public Object put(Object key , Object value)
2. public void putAll(Map map);
3. public Object remove(Object key);
4. public Object get(Object key);
5. public int size();
6. public boolean isEmpty();
7. public void clear();
8. public boolean containsKey(Object key)
9. public boolean containsValue(Object value)
10. public Set keySet();
11.public Collection values()