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Thread: Unchecked or Unsafe Operations

  1. #1
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    Default Unchecked or Unsafe Operations

    I am compiling my code and I keep getting an unsafe or unchecked operations warning. I know it is just a warning, but I still need it to disappear without suppressing it. I've researched and it looks like it comes from ArrayList generalizations, but I don't know how to fix it. I've included the relevant portions of code.

    //Variables at the top of class
    	Vector[] adjacency;
     
    //Constructor
     		adjacency = new Vector[N*N];
     		for(int i=0;i<adjacency.length;i++)
     			adjacency[i] = new Vector<Integer>();
    //In a called method - node & neighbor are both ints
     		if(node<neighbor) 
    			 adjacency[node].add(neighbor); 
     		else 
     			adjacency[neighbor].add(node);
     
    //In another called method  - node & neighbor are both ints
    				if(node<neighbor)
    					if(!adjacency[node].contains(neighbor)) {
    						//Add to graph and increase count
    						adjacency[node].add(neighbor);
    						count++;
    					}
    				if(neighbor<node)
    					if(adjacency[neighbor].contains(node)) {
    						//Add to graph and increase count
    						adjacency[neighbor].add(node);
    						count++;
    					}

    Here is the warning I get from the compiler when I ask for details (-Xlint:unchecked)

    travis-mac:Project3 Travis$ javac TMMp3.java -Xlint:unchecked
    TMMp3.java:76: warning: [unchecked] unchecked call to add(E) as a member of the raw type java.util.Vector
    			 adjacency[node].add(neighbor); 
    			                    ^
    TMMp3.java:78: warning: [unchecked] unchecked call to add(E) as a member of the raw type java.util.Vector
     			adjacency[neighbor].add(node);
     			                       ^
    TMMp3.java:147: warning: [unchecked] unchecked call to add(E) as a member of the raw type java.util.Vector
    						adjacency[node].add(neighbor);
    						                   ^
    TMMp3.java:153: warning: [unchecked] unchecked call to add(E) as a member of the raw type java.util.Vector
    						adjacency[neighbor].add(node);
    						                       ^
    4 warnings

    If you can help me get this warning to go away that would be great!

    Thanks,
    Travis


  2. #2
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    Default Re: Unchecked or Unsafe Operations

    Vector[] adjacency;
    Your problem is when you create the array but I'm not sure you can use Generics with arrays. Why not make a Vector of Victors err Vectors? Roger!
    Vector<Vector<Integer>> adjacency = new Vector<Vector<Integer>> ();

  3. #3
    Super Moderator Json's Avatar
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    Default Re: Unchecked or Unsafe Operations

    And why not use List and ArrayList as Vector is old and slow and if you need thread safety you can use Collections.synchronizedList.

    // Json

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