Operation between the two sets in java

// Create the sets
Set set1 = new HashSet();
Set set2 = new HashSet();

// Add elements to the sets ... // Copy all the elements from set2 to set1 (set1 += // set2)
// set1 becomes the union of set1 and set2
set1.addAll(set2);

// Remove all the elements in set1 from set2 (set1 -= set2) // set1 becomes the
// asymmetric difference of set1 and set2
set1.removeAll(set2);

// Get the intersection of set1 and set2
// set1 becomes the intersection of set1 and set2
set1.retainAll(set2);

// Remove all elements from a set
set1.clear();