HashSet Collection

• What is HashSet collection  (class hierarchy)
• Iterate/loop elements/string objects of HashSet collection in java8 
• Convert HashSet to TreeSet in java (example)
• Convert HashSet of string to Array in java
• Convert HashSet of String objects to ArrayList in java

LinkedHashSet Collection:

• What is LinkedHashSet collection (class hierarchy)
• Iterate or loop LinkedHashSet collection of String objects
• Convert LinkedHashSet of String objects to TreeSet collection
• Convert LinkedHashSet of String objects to ArrayList collection 
• Convert LinkedHashSet collection of String objects to Array in java

TreeSet Collection

• What is TreeSet collection (class hierarchy)
• Sort user defined objects using TreeSet in java (Comparator interface)
• Sort user defined objects in TreeSet (using Comparable)