Generic Classes

}The concept of a data structure, such asa stack, can be understood independently of the element type it manipulates. 

}Generic classes provide a means for describing the concept of a stack (or any other class) in a type-independent manner. 

}These classes are known as parameterized classes or parameterized types because they accept one or more type parameters. 

Raw Types

}It’salso possible to instantiate generic class Stack without specifying a type argument, as follows:–

// no type-argument specified
  Stack objectStack = new Stack( 5 ); 

◦objectStack is said to have a raw type

◦The compiler implicitly uses type Object throughout the generic class for each type argument. 

◦The preceding statement creates a Stack that can store objects of any type. 

◦Important for backward compatibility with prior versions of Java. 

◦Raw-type operations are unsafe and could lead to exceptions.

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