4/1/2023 0 Comments Contains method map javaReturns null if the Map contains no mapping for this key. Parameters: value - value whose presence in this Map is to be tested. This operation will probably require time linear in the Map size for More formally, returns true if and only if this Map contains at Public abstract boolean containsValue(B value) NullPointerException -key is null and this Map does not Throws: ClassCastException -key is of an inappropriate type for Parameters: key - key whose presence in this Map is to be tested. Public abstract boolean containsKey(A key) Returns a Collection view of the values contained in this Map Returns the number of key-value mappings in this Map. Removes the mapping for this key from this Map if present (optional Returns a Set view of the keys contained in this MapĪssociates the specified value with the specified key in this MapĬopies all of the mappings from the specified Map to this Map Returns true if this Map contains no key-value mappings. Returns the value to which this Map maps the specified key. Returns a Set view of the mappings contained in this MapĬompares the specified Object with this Map for equality. Returns true if this Map maps one or more keys to the specified value. Returns true if this Map contains a mapping for the specified key. Removes all mappings from this Map (optional operation). See also: HashMap, ArrayMap, TreeMap, Hashtable, Collection, Set To enforce this recommendation (as interfaces cannot contain constructors)īut all of the general-purpose Map implementations in the JDK comply. Map, producing an equivalent Map of the desired class. In effect, the latter constructor allows the user to copy any Which creates a new Map with the same key-value mappings as itsĪrgument. "standard" constructors: A void (no arguments) constructor which createsĪn empty Map, and a constructor with a single argument of type Map, Guarantees as to their order others, like HashMap, do not.Īll general-purpose Map implementation classes should provide two Some Map implementations, like TreeMap and ArrayMap, make specific In which the iterators on the Map's Collection views return their elements. The order of a Map is defined as the order Map's contents to be viewed as a Set of keys, Collection of values, or Set The Map interface provides three Collection views, which allow a This Interface is implemented by HashMap, This interface takes the place of Dictionary, which was a totally abstractĬlass rather than an interface.
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