Class Level type Parameter

Type parameters are used as Type placeholders
public class List<T>  { }
Here T is a type parameter.
Here List<T>  is a container for T objects.
T can be any class Type.
List<T> can be List<String>, List<Integer> , List<User>

Similarly
Interface Map<K,V> holds two type parameters
It can be any class types.

class Forest<T>{
    private T t;
    public Forest(T t) {
        this.t=t;
    }
    public T getT() {
        return t;
    }
}
public class TypeParamFlight {
    public static void main(String[] bag) {
        String str = new String("dove");
        Forest<String> f1 = new Forest<String>(str);
        String strVal = f1.getT();
        System.out.println("strVal: "+strVal);
       
        Forest<Integer> f2 = new Forest<Integer>(10);
        Integer intVal = f2.getT();
        System.out.println("intVal: "+intVal);
    }
}
Output
strVal: dove
intVal: 10