public void testHashcode() {
        CategoryTextAnnotation a1 = new CategoryTextAnnotation(
            "Test", "Category", 1.0
        );
        CategoryTextAnnotation a2 = new CategoryTextAnnotation(
            "Test", "Category", 1.0
        );
        assertTrue(a1.equals(a2));
        int h1 = a1.hashCode();
        int h2 = a2.hashCode();
        assertEquals(h1, h2);