* Runnable interface have only one method that is run()
* equals() method checks for only object types
* Garbage collection algorithm in
java is vendor implemented
* A class inside a method can only have access to final variables.
* Strings are implemented as a class for which java overloads the + operator.
* To get the size of an array u must use the lenght property of an array ( array-var.length)
* To get the size of a
String or StringBuffer objects u must use the length() method.
( string_var.length(), stringbuffer_var.length())
* The instanceof operator can be used to determine if a reference is an instance of a particular primitive wrapper class.
* The instanceof operator will always return ture if you ask if a reference is an instance of the object class.
* Interfaces can't contain constructors.
* Interfaces can't be instantiated.
* Constructors may be overloaded but can't be overriden.
* constructors can be declared private.
* Anonymous class can't have a constructor.
* A collection for storing bits as on-off information like a vector of bits.
* Collection is the root interface in the collection hierarchy
* Set and List interfaces extends from Collection interface.
* List is an ordered list and does allow duplicates( it can have more than one null element) , and search for elements in the list is by their integer index.
* Set is a unordered collection and does not allow duplicates