Implementing Graph in Java, getting raw type error

Question

I'm trying to implement a Graph as an adjacency list, with the code below. I'm getting a raw type error on line 9.

Edit: Just want to clarify, I get an unchecked/unsafe operation error, then when I compile with Xlint, I get the raw type error.

import java.util.LinkedList;

public class AdjListGraph{
    private int vertices;
    private LinkedList<Integer>[] AdjList;

    public AdjListGraph(int v){
        this.vertices = v;
        AdjList = (LinkedList<Integer>[]) new LinkedList[v];
        for (int i = 0; i < v; i++){
            AdjList[i] = new LinkedList<Integer>();
        }
    }

Sorry should be line 9, this is the problematic line "AdjList = (LinkedList[]) new LinkedList[v];". I'm compiling it in the command line. — user3002315, Dec 06 '16 at 01:37
LinkedList does not give great performance for random access. See http://stackoverflow.com/questions/10656471/performance-differences-between-arraylist-and-linkedlist — dnault, Dec 06 '16 at 01:40
Possible duplicate of [How to create a generic array in Java?](http://stackoverflow.com/questions/529085/how-to-create-a-generic-array-in-java) — Tim Biegeleisen, Dec 06 '16 at 01:45

score 1 · Accepted Answer · edited May 23 '17 at 12:08

1

There's unsafe typecast in line 9.
Do not mix arrays and generics: LinkedList<Integer>[] is a bad smell. And that's the real problem. You can't have arrays of generic classes. Java simply doesn't support it. Read more in Q: How to create a generic array in Java?.

edited May 23 '17 at 12:08

Community

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answered Dec 06 '16 at 02:20

naXa

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So should I use a collection instead? – user3002315 Dec 06 '16 at 02:27

Implementing Graph in Java, getting raw type error

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