public HashMap<String, Mass> makeMasses() {
		float x;
		float y;
		float mass;
		double vx;
		double vy;

		NodeList nodes = myDoc.getElementsByTagName(MASS);
		for (int i = 0; i < nodes.getLength(); i++) {
			// Default values
			vx = 0;
			vy = 0;
			mass = 5f;

			Node massItem = nodes.item(i);
			NamedNodeMap nodeMap = massItem.getAttributes();

			x = Float.parseFloat(nodeMap.getNamedItem(X).getNodeValue());
			y = Float.parseFloat(nodeMap.getNamedItem(Y).getNodeValue());
			try {
				mass = Float.parseFloat(nodeMap.getNamedItem(MASS)
						.getNodeValue());
			} catch (Exception e) {
			}

			try {
				vx = Double
						.parseDouble(nodeMap.getNamedItem(VX).getNodeValue());
			} catch (Exception e) {
			}

			try {
				vy = Double
						.parseDouble(nodeMap.getNamedItem(VY).getNodeValue());
			} catch (Exception e) {
			}

			myMassMap.put(nodeMap.getNamedItem(ID).getNodeValue(),
					new MovableMass(x, y, vx, vy, mass));
		}

		nodes = myDoc.getElementsByTagName(FIXED);
		for (int i = 0; i < nodes.getLength(); i++) {
			Node massItem = nodes.item(i);
			NamedNodeMap nodeMap = massItem.getAttributes();

			x = Float.parseFloat(nodeMap.getNamedItem(X).getNodeValue());
			y = Float.parseFloat(nodeMap.getNamedItem(Y).getNodeValue());

			myMassMap.put(nodeMap.getNamedItem(ID).getNodeValue(), new Mass(x,
					y, 0));
		}
		return myMassMap;
	}