java.util.Arrays is helper class

Author: tugul

collections/ArrayVsArrayList.java

@@ -8,8 +8,8 @@
  * Dimension: Array can be multi-dimensional while ArrayList is only single dimensional
  * Primitive: ArrayList can't store primitives, instead can store their wrapper objects 
  * Generics: ArrayList supports generics, so it is type-safe
- * Adding an element: Array element is added through asignment operator, while ArrayList use add() method 
- * Length: Array has length variable while ArraList has size() method
+ * Adding an element: Array element is added through assignment operator, while ArrayList use add() method 
+ * Length: Array has length variable while ArrayList has size() method
  * Performance: Array is faster while ArrayList is bit slower, especially when comparing
  * Sorting: 
  * 	Array      : Arrays.sort(T[] a);

collections/README.md

@@ -1,26 +1,34 @@
-Collections framework has four main data structure types (list, set, queue and map). 
-List, set and queue interfaces extends Collection interface which extends Iterable interface. 
+# Collections framework
+Collections framework has four main data structure types which are **list**, **set**, **queue** and **map**. 
+``List``, ``Set`` and ``Queue`` interfaces in ``java.util`` extends ``java.util.Collection`` interface which extends ``java.lang.Iterable`` interface. 
 
-##### 1. List — Ordered collection of elements that can duplicate
-- ArrayList: Standard re-sizable list.
-- LinkedList: implements both List and Deque. Can easily add/remove from beginning or end.
-- Vector: Older version of ArrayList, thread-safe.
-- Stack: Older last-in, first-out class, newer version ArrayDeque is more flexible
+## Main data structure types
+### 1. **List** — Ordered collection of elements that can duplicate
+- ``ArrayList``: Standard re-sizable list.
+- ``LinkedList``: implements both ``List`` and ``Deque``. Can easily add/remove from beginning or end.
+- ``Vector``: Older version of ``ArrayList``, thread-safe.
+- ``Stack``: Older last-in, first-out class, newer version ``ArrayDeque`` is more flexible
 
-##### 2. Set —Does not allow duplicates
-- HashSet: Uses hashcode() to find unordered elements.
-- TreeSet: implements NavigableSet which extends SortedSet. Does not allow null values.
+### 2. **Set** — Does not allow duplicates
+- ``HashSet``: Uses ``hashcode()`` to find unordered elements.
+- ``TreeSet``: implements ``NavigableSet`` which extends ``SortedSet``. Does not allow null values.
 
-##### 3. Queue —Orders elements for processing
-- LinkedList: Can easily add/remove from beginning or end.
-- ArrayDeque: First-in, first-out or last-in, first-out. Does not allow null values.
+### 3. **Queue** — Orders elements for processing
+- ``LinkedList``: Can easily add/remove from beginning or end.
+- ``ArrayDeque``: First-in, first-out or last-in, first-out. Does not allow null values.
 
-##### 4. Map —Maps unique keys to values
-- HashMap: Uses hashcode() to find keys, allows null key
-- TreeMap: Sorted map. Does not allow null keys.
-- HashTable: Older version of HashMap. Does not allow null keys or values.
+### 4. **Map** — Maps unique keys to values
+- ``HashMap``: Uses ``hashcode()`` to find keys, allows null key
+- ``TreeMap``: Sorted map. Does not allow null keys.
+- ``HashTable``: Older version of ``HashMap``. Does not allow null keys or values.
 
-Sorting:
- - Collections.sort(List\<T extends Comparable> list)
- - Collections.sort(List\<T> list, Comparator comparator)
- - Use TreeMap to sort Map by key or value
+## Sorting
+ - ``Collections.sort(List\<T extends Comparable> list)``
+ - ``Collections.sort(List\<T> list, Comparator comparator)``
+ - Use ``TreeMap`` to sort ``Map`` by key or value
+
+ ## Helper classes
+ ### ``java.util.Arrays``
+ It is a helper class for common unitility tasks on manipulating arrays such as _sorting_ and _searching_ in arrays
+
+