Question

what is a generic class???can u provide a simple demo program??

Answer 1

A class is generic if it declares one or more type variables. These type variables are known as the type parameters of the class. (According to Java Language Specification)
Example of generic class GeneralPrinter with parameter <T>:
class GeneralPrinter<T> {
private T val;

public GeneralPrinter(T arg) {
val = arg;
}

public String toString() {
return "{" + val + "}";
}

public T getValue() {
return val;
}
}

public class Test {
public static void main(String[] args) {
GeneralPrinter<Integer> value1 = new GeneralPrinter<Integer>(new Integer(10));
System.out.println(value1);
Integer intValue1 = value1.getValue();
GeneralPrinter<String> value2 = new GeneralPrinter<String>("Hello world");
System.out.println(value2);

}
}