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Incompatible Java generics types

I made this code:

import java.util.LinkedList;

public class Node<T> {
private T data;
private LinkedList<T> children;
public Node(T data) {
    this.data = data;
    this.children = new LinkedList<T>();
}
public T getData() {
    return this.data;
}
public LinkedList<T> getChildren(){
    return this.children;
}
}


public class Graph <T> implements Network<T> {
private Node source;
private Node target;
private ArrayList<Node> nodes = new ArrayList<Node>();


public Graph(T source,T target) {
    this.source = new Node(source);
    this.target = new Node(target);


}


public T source() {
    return source.getData();
}

public T target() {
    return target.getData();
}

I am getting this error on source () and target (): required T found java.lang.Object why? return type of getData () function is T (generic return type)

+3


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2 answers 


private Node source;
private Node target;


It should be Node<T>

. Likewise on several of the following lines. The compiler will give you a warning. Pay attention to this. (When you mix raw types and generics, the Java Language Spec often requires the compiler to opt out.)

+3


source


Replace Node

with Node<T>

in classGraph 



public class Graph<T> implements Network<T> {
    private Node<T> source;
    private Node<T> target;
    private ArrayList<Node> nodes = new ArrayList<Node>();

    public Graph(T source, T target) {
        this.source = new Node<T>(source);
        this.target = new Node<T>(target);

    }

    public T source() {
        return source.getData();
    }

    public T target() {
        return target.getData();
    }
}
0


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