I have tried version 1.2.47 , 1.2.58 , 1.2.68.noneautotype , 1.2.76 , but failed with different errors.

public static class Foo {
        private String name;
        private String value;

        public Foo(String name, String value) {
            this.name = name;
            this.value = value;
        }

        public String getName() {
            return name;
        }

        public String getValue() {
            return value;
        }

    }

    @Test
    public void test3() throws Exception {
        Foo value = new Foo("aaa", "bbb");
        Foo value2 = new Foo("aaa", "bbb");
        Map<String, Object> object = new HashMap<>();
        object.put("127.0.0.1:1111", value);
        String s = JSON.toJSONString(new Object[]{object, value, value2});
        assertEquals(
                "[{\"127.0.0.1:1111\":{\"name\":\"aaa\",\"value\":\"bbb\"}},{\"$ref\":\"$[0].127\\\\.0\\\\.0\\\\.1\\\\:1111\"},{\"name\":\"aaa\",\"value\":\"bbb\"}]",
                s);
        JSONArray objects = JSON.parseArray(s);
        Foo value1 = JSON.toJavaObject(objects.getJSONObject(1), Foo.class);
        assertNotNull(value1);
        assertEquals(value.getName(), value1.getName());
        assertEquals(value.getValue(), value1.getValue());
    }