Java Generics - List

• Only instances of that type can be inserted

            List<T> list = new ArrayList<T>();

• list − object of List interface.
• T − The generic type parameter passed during list declaration.

Example:

import java.util.ArrayList;
import java.util.List;

public class GenericList <T>{

    List<T> wrappedList;

    public GenericList() {
        this.wrappedList = new ArrayList<>();
    }
    public GenericList(List<T> wrappedList) {
        this.wrappedList = wrappedList;
    }

    //get method with custom one
    public T myGet(int index){
        return  wrappedList.get(index);
    }

    //add method with custom one
    public void myAdd(T o){
        wrappedList.add(o);
    }

    //remove method with custom one
    public T myRemove(int index){
        return  wrappedList.remove(index);
    }

    @Override
    public String toString() {
        return wrappedList.toString();
    }

    public static void main(String[] args) {

        GenericList<CharSequence> g = new GenericList<>();
        g.myAdd("hi");
        g.myAdd("hello");
        var o = g.myGet(0);
        System.out.println("Element 0 = "+o);

        System.out.println("Wrapped List "+g.myRemove(0));

    }

}