Creating a HashSet : HashSet « Collections « Java Tutorial

The HashSet class provides four constructors broken into two sets. The first three constructors create empty sets of varying sizes:

public HashSet()
public HashSet(int initialCapacity)
public HashSet(int initialCapacity, int loadFactor)

When creating any collection, it is always best to have the local variable be of the interface type,

Set set = new HashSet().

For easier to change the set to a TreeSet or some other set implementation.

The fourth constructor acts as a copy constructor.

public HashSet(Collection col)

If the original collection had duplicates, only one of the duplicates will be in the final created set.

9.19.1.Set and HashSet
9.19.2.Creating a HashSet
9.19.3.An easy way to initialize a set without manually adding each element
9.19.4.Adding Single Elements: the add() method
9.19.5.Adding Another Collection with the addAll() method: public boolean addAll(Collection c)
9.19.6.Removing All Elements: public void clear()
9.19.7.Removing Single Elements: public boolean remove(Object element)
9.19.8.Removing Another Collection: public boolean removeAll(Collection c)
9.19.9.Retaining Another Collection: public boolean retainAll(Collection c)
9.19.10.Fetching Elements: to work with all of the elements of the set
9.19.11.Checking for Existence: the contains() method reports if a specific element is within the set
9.19.12.the containsAll() method checks if a set contains another whole collection
9.19.13.To find out how many elements are in a set, use the size() method
9.19.14.Checking for no elements in the set: use the isEmpty() method instead
9.19.15.Copying and Cloning Sets: public Object clone()
9.19.16.HashSet implements the empty Serializable interface
9.19.17.Converting elements in a set to Array: public Object[] toArray()
9.19.18.public Object[] toArray(Object[] a)
9.19.19.The HashSet class defines equality through its equals() method: public boolean equals(Object o)
9.19.20.Find maximum element of HashSet
9.19.21.Find Minimum element of HashSet
9.19.22.Get Enumeration over HashSet
9.19.23.Get Synchronized Set from HashSet
9.19.24.Check if a particular element exists in HashSet
9.19.25.Copy all elements of HashSet to an Object Array
9.19.26.Get Size of HashSet
9.19.27.Iterate through elements of HashSet
9.19.28.Remove all elements from HashSet
9.19.29.Remove specified element from HashSet
9.19.30.Integer value set
9.19.31.Listing the Elements of a Collection(iterate over the elements of set or list)
9.19.32.Making a Collection Read-Only
9.19.33.Convert array to Set
9.19.34.Create unique lists of items?