Here is my JUnit test:

```
package general;

import io.vertx.core.json.JsonObject;
import io.vertx.ext.unit.TestContext;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

class Foo {

    String loaf = "";

    static boolean dog() {
        return true;
    }
}

public class GeneralTest {  

    @Test
    public void test() {
        JsonObject v = new JsonObject();
        v.put("loaf","box");
        var k = v.mapTo(Foo.class);
        System.out.println(k);
    }
}

```

when I run it I get this error:

```
java.lang.IllegalArgumentException: Unrecognized field "loaf" (class general.Foo), not marked as ignorable (0 known properties: ])
 at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: general.Foo["loaf"])
        at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:3750)
        at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:3668)
        at io.vertx.core.json.JsonObject.mapTo(JsonObject.java:106)
        at general.GeneralTest.test(GeneralTest.java:33)

```

I can't figure out why it's not accepting the Foo.class as valid?