Which of these methods Map class is used to obtain an element in the Map having a specific key?

All Known Implementing Classes:AbstractMap.SimpleEntry, AbstractMap.SimpleImmutableEntryEnclosing interface:Map<K,V>
```
public static interface Map.Entry<K,V>
```
A map entry (key-value pair). The
Inhaltsverzeichnis Show
Map.entrySet
method returns a collection-view of the map, whose elements are of this class. The only way to obtain a reference to a map entry is from the iterator of this collection-view. These
Map.Entry
objects are valid only for the duration of the iteration; more formally, the behavior of a map entry is undefined if the backing map has been modified after the entry was returned by the iterator, except through the
setValue
operation on the map entry.
Since: 1.2See Also:Map.entrySet()

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods

Modifier and Type	Method and Description
`static <K extends Comparable<? super K>,V> Comparator<Map.Entry<K,V>>`	`comparingByKey()` Returns a comparator that compares `Map.Entry` in natural order on key.
`static <K,V> Comparator<Map.Entry<K,V>>`	`comparingByKey(Comparator<? super K> cmp)` Returns a comparator that compares `Map.Entry` by key using the given `Comparator`.
`static <K,V extends Comparable<? super V>> Comparator<Map.Entry<K,V>>`	`comparingByValue()` Returns a comparator that compares `Map.Entry` in natural order on value.
`static <K,V> Comparator<Map.Entry<K,V>>`	`comparingByValue(Comparator<? super V> cmp)` Returns a comparator that compares `Map.Entry` by value using the given `Comparator`.
`boolean`	`equals(Object o)` Compares the specified object with this entry for equality.
`K`	`getKey()` Returns the key corresponding to this entry.
`V`	`getValue()` Returns the value corresponding to this entry.
`int`	`hashCode()` Returns the hash code value for this map entry.
`V`	`setValue(V value)` Replaces the value corresponding to this entry with the specified value (optional operation).

- Method Detail
  - getKey
```
K getKey()
```
    Returns the key corresponding to this entry.
    Returns:the key corresponding to this entryThrows:IllegalStateException - implementations may, but are not required to, throw this exception if the entry has been removed from the backing map.
  - getValue
```
V getValue()
```
    Returns the value corresponding to this entry. If the mapping has been removed from the backing map (by the iterator's
    remove
    operation), the results of this call are undefined.
    Returns:the value corresponding to this entryThrows:IllegalStateException - implementations may, but are not required to, throw this exception if the entry has been removed from the backing map.
  - setValue
```
V setValue(V value)
```
    Replaces the value corresponding to this entry with the specified value (optional operation). (Writes through to the map.) The behavior of this call is undefined if the mapping has already been removed from the map (by the iterator's
    remove
    operation).
    Parameters:value - new value to be stored in this entryReturns:old value corresponding to the entryThrows:UnsupportedOperationException - if the put operation is not supported by the backing mapClassCastException - if the class of the specified value prevents it from being stored in the backing mapNullPointerException - if the backing map does not permit null values, and the specified value is nullIllegalArgumentException - if some property of this value prevents it from being stored in the backing map IllegalStateException - implementations may, but are not required to, throw this exception if the entry has been removed from the backing map.
  - equals
```
boolean equals(Object o)
```
    Compares the specified object with this entry for equality. Returns
    true
    if the given object is also a map entry and the two entries represent the same mapping. More formally, two entries
    e1
    and
    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
    equals
    method works properly across different implementations of the
    Map.Entry
    interface.
    Overrides:equals in class ObjectParameters:o - object to be compared for equality with this map entryReturns:true if the specified object is equal to this map entrySee Also: Object.hashCode(), HashMap
  - hashCode
```
int hashCode()
```
    Returns the hash code value for this map entry. The hash code of a map entry
    e
    is defined to be:
```
     (e.getKey()==null   ? 0 : e.getKey().hashCode()) ^
     (e.getValue()==null ? 0 : e.getValue().hashCode())
 
```
    This ensures that
    e1.equals(e2)
    implies that
    e1.hashCode()==e2.hashCode()
    for any two Entries
    e1
    and
    e2
    , as required by the general contract of
    Object.hashCode
    .
    Overrides:hashCode in class ObjectReturns:the hash code value for this map entrySee Also:Object.hashCode(), Object.equals(Object), equals(Object)
  - comparingByKey
```
static <K extends Comparable<? super K>,V> Comparator<Map.Entry<K,V>> comparingByKey()
```
    Returns a comparator that compares Map.Entry in natural order on key.
    The returned comparator is serializable and throws NullPointerException when comparing an entry with a null key.
    Type Parameters:K - the Comparable type of then map keysV - the type of the map valuesReturns:a comparator that compares Map.Entry in natural order on key.Since:1.8See Also:Comparable
  - comparingByValue
```
static <K,V extends Comparable<? super V>> Comparator<Map.Entry<K,V>> comparingByValue()
```
    Returns a comparator that compares Map.Entry in natural order on value.
    
    The returned comparator is serializable and throws NullPointerException when comparing an entry with null values.
    Type Parameters:K - the type of the map keysV - the Comparable type of the map valuesReturns: a comparator that compares Map.Entry in natural order on value.Since:1.8See Also:Comparable
  - comparingByKey
```
static <K,V> Comparator<Map.Entry<K,V>> comparingByKey(Comparator<? super K> cmp)
```
    Returns a comparator that compares Map.Entry by key using the given Comparator.
    The returned comparator is serializable if the specified comparator is also serializable.
    Type Parameters: K - the type of the map keysV - the type of the map valuesParameters:cmp - the key ComparatorReturns:a comparator that compares Map.Entry by the key.Since:1.8
  - comparingByValue
```
static <K,V> Comparator<Map.Entry<K,V>> comparingByValue(Comparator<? super V> cmp)
```
    Returns a comparator that compares Map.Entry by value using the given Comparator.
    The returned comparator is serializable if the specified comparator is also serializable.
    Type Parameters:K - the type of the map keysV - the type of the map valuesParameters:cmp - the value ComparatorReturns:a comparator that compares Map.Entry by the value.Since:1.8

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Which of these methods map class is used to obtain an element in the map having specified key?

Explanation: keySet() methods is used to get a set containing all the keys used in a map.

Which method in MAP is used to obtain an element?

The get() method returns a specified element from a Map object.

Which method is used add an element and corresponding key to a map?

set() The set() method adds or updates an entry in a Map object with a specified key and a value.

Which of these methods is used to add elements in properties at a specific location?

5. Which of these methods is used to add elements in vector at specific location? Explanation: addElement() is used to add data in the vector, to obtain the data we use elementAt() and to first and last element we use firstElement() and lastElement() respectively. 6.