The Java Generics programming
is introduced in J2SE 5 to deal with type-safe objects.
•Before generics, we can store any type of objects in collection i.e. non-generic. Now generics, forces the java programmer to store specific type of objects.
Advantage of Java
Generics
•There are mainly 3
advantages of generics.
They
are as follows:
»1) Type-safety : We
can hold only a single type of objects in generics. It doesn’t allow to store
other objects.
»2) Type casting is
not required: There is no need to typecast the object.
»Before Generics, we
need to type cast.
List list = new ArrayList();
list.add("hello");
String s = (String) list.get(0);//typecasting
»After Generics, we
don't need to typecast the object.
List<String> list = new ArrayList<String>();
list.add("hello");
String s = list.get(0);
»3)
Compile-Time Checking: It is checked at compile time so problem
will not occur at runtime. The good programming strategy says it is far better
to handle the problem at compile time than runtime.
List<String> list = new ArrayList<String>();
list.add("hello");
list.add(32);//Compile Time Error
Generic
class
•A class that can refer
to any type is known as generic class. Here, we are using T type
parameter to create the generic class of specific type.
Type Parameters
•The type
parameters naming conventions are important to learn generics thoroughly. The
commonly type parameters are as follows:
–T - Type
–E - Element
–K - Key
–N - Number
–V – Value
Generic Method
Like generic class, we
can create generic method that can accept any type of argument.
