Comparable and Comparator in Java are two interfaces used to sort a collection of objects. The obvious question is why two interfaces when they both do the same task of sorting the objects. In this post we’ll see what are Comparable and Comparator interfaces in Java, why both are required…
In Java Collections framework you would have seen that the Collections like ArrayList, HashMap return an iterator that is termed as fail-fast iterator where as the concurrent collections like CopyOnWriteArrayList, ConcurrentHashMap return an iterator that is termed as fail-safe iterator. In this post we’ll see what are fail-fast and fail-safe…
If you have to store only unique elements i.e no duplicates in your Java application you’d probably choose to use one of the Set implementation in Java; HashSet, TreeSet or LinkedHashSet. Though all these Set implementations store unique elements but they do differ on the points like ordering of elements,…
In Java Collections framework there are two general-purpose List implementations— ArrayList and LinkedList. In this post we’ll see the differences between ArrayList and LikedList in Java to understand these two implementations better. Knowing the differences between ArrayList and LikedList will also help you to determine which implementation is better in…
TreeSet in Java is one of the implementation of the Set interface. How it differs from the other popular implementation HashSet is that unlike HashSet which is unordered, TreeSet stores its element in sorted order. The elements in TreeSet are ordered using their natural ordering, or by a Comparator provided…
LinkedHashSet in Java is also one of the implementation of the Set interface like HashSet and Treeset. How LinkedHashSet differs from the other implementation HashSet is that unlike HashSet which is unordered, LinkedHashSet is an ordered collection, it maintains iteration ordering, which is the order in which elements were inserted…
If you have to store (key, value) pair in your Java application you will use one of the hash table based implementation present in java.util package and the options are HashMap, LinkedHashMap, TreeMap and HashTable. The Map implementation chosen by you will be based on the criteria whether synchronization is…
This post shows how to synchronize HashMap in Java and the HashMap’s thread safe alternative which can be used. HashMap is not thread safe If HashMap is accessed by multiple threads concurrently, and at least one of the threads modifies the map structurally, you must synchronize HashMap externally. Note that…
TreeMap in Java is one of the implementation of the Map interface. How it differs from the other implementation HashMap is that unlike HashMap which is unordered, TreeMap is Sorted. TreeMap is sorted according to the natural ordering of its keys by default. If you want different sort ordering then…
LinkedHashMap in Java is also one of the implementation of the Map interface. How it differs from the other implementation HashMap is that unlike HashMap which is unordered, LinkedHashMap is ordered. LinkedHashMap class in Java also extends HashMap apart from implementing Map interface. LinkedHashMap maintains a doubly-linked list running through…