Collection Framework

Sorting using Comparable Interface

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The Comparable interface is used by the Collection.sort() method and the java.util.Array.sort() method to sort Lists and array of objects, respectively. To implement Comparable, a class must implement a single method, compareTo().  Read the rest of this entry »

Sort an Array using Comparator

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Comparator is an interface which comes under java.util package is useful to impose a total ordering on a collection of elements (Objects) of an array into ascending or descending order.

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EnumMap in Java

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EnumMap is specialized Map implementation designed and optimized for using Java Enum as key. EnumMap in Java is added on JDK  5 release. There are some similarities as well as differences between EnumMap and HashMap which you can find hereFollowings are the features of EnumMap. Read the rest of this entry »

TreeMap in Java

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The TreeMap class implements the Map interface which store key-value pairs in tree data structure. It provides an efficient means of storing key/values pairs in sorted order.

Followings are the features of TreeMap.

  1. It contains only unique elements.
  2. It can’t have null key but can have multiple null values.
  3. It is not synchronized i.e not safe for multi-threaded application.
  4. It is same as HashMap instead maintains ascending order.

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