* @param cause The cause of the exception.
     */
    public ContainerNotAvailableException(final String componentName, final Throwable cause) {
        super(componentName + " is not available.", cause);
        this.componentName = componentName;
    }

    /**
     * Constructor with cause only.
     * @param cause The cause of the exception.
     */

        String componentName = "testComponent";

        ComponentUtil.register(first, componentName);
        String retrieved1 = ComponentUtil.getComponent(componentName);
        assertSame(first, retrieved1);

        ComponentUtil.register(second, componentName);
        String retrieved2 = ComponentUtil.getComponent(componentName);
        assertSame(second, retrieved2);
    }