CODEWITHSUNDEEP
javagenericstype-erasure
WelcomeTo
WelcomeTo

Reputation: 20571

Create generic List

How I can create genric List in Java? I also can pass Class<T> instance to the method.

Like this: 

public static <T> List<T> createList(Class<T> clazz) {
    List<T> list = new ArrayList<T>();

    list.add(clazz.newInstance());

    return list;
}

Upvotes: 0

Views: 13328

Answers (2)

Mr.Cool
Mr.Cool

Reputation: 1555

if you want to pass the instance to list means you can try this

public class info  {

    private int Id;

    public void setId(int i_Id) {
    this.Id = i_Id;
    }

    public int getId() {
    return this.Id;
    }

}

class two{
    private List<info> userinfolist;

    userinfolist= new ArrayList<info>();

    //now you can add a data by creating object to that class

     info objinfo= new info();
     objinfo.setId(10);
     userinfolist.add(objinfo); .//add that object to your list
     }

Upvotes: 0

Javier
Javier

Reputation: 12398

I don't understand why you want a method at all. You can just do new ArrayList<String>(), new ArrayList<Integer>(), etc.

If you want to write it as a method, do

 public static <T> List<T> createList() {
    return new ArrayList<T>();
 }

The return type List<T> is inferred by the compiler.

Upvotes: 5

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