No more handles after limiting amount of generated SWT objects

Question

My application used multiple Hashmaps to store Color and Image objects that were randomly generated whenever a new Key came up (which could be an infinite amount).

To reduce memory usage I am using a Hashfunction to limit the amount of randomly generated Colors and Images to 229. Weirdly enough when I was storing virtually infinite Colors and Images, the program did run without major issues (except for the leak of course).

Now that I'm trying to re-use a limited set of Objects strangely after a few seconds I keep getting the exception :

org.eclipse.swt.SWTException: Failed to execute runnable (org.eclipse.swt.SWTError: No more handles)

The generation of the maps looks something like this:

static Map<Integer, Color> color = new Hashtable<>();
    private static final int MAX_COLORS = 229;

    private static void generateColor(String typeName) {
        if (mapping.containsKey(typeName)) {
            return;
        }

        Color c = generateRandomColor(typeName);
        color.put(typeNameHash(typeName), c);
    }

    private static Color generateRandomColor(String typeName) {
        if(color.containsKey(typeNameHash(typeName))){
            return color.get(typeNameHash(typeName));
        }
        int red = random.nextInt(255);
        int green = random.nextInt(255);
        int blue = random.nextInt(255);
        return new Color(Display.getCurrent(), red, green, blue);
    }

    private static int typeNameHash(String typeName){
        return Math.abs(typeName.hashCode())%MAX_COLORS;
    }

How is it possible that now, that I should have less objects, I'm running into this kind of exception so fast?

Thanks in advance!

Answer 1

The solution to my issue here was, that I was still using the Strings as keys, instead of calling the hash-function on the strings in some instances. Since HashMaps take Objects-type for keys the compiler did not warn me about that.

Checking all code parts where I inserted into the Hashmap and making sure the hash-function was used everywhere resolved the issue.