Java Reflection accessing public fields

I am writing a custom Serializer (Jackson JSON) for List class, this list could be inferred with different class types, so I'll need to grab object fields values using reflection.

Note, all this classes has public values (no setters and getters), so Invoking the getter will not be an option.

This is what I get so far:

package com.xxx.commons.my.serializer;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;
import org.apache.commons.lang3.reflect.FieldUtils;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.math.BigDecimal;
import java.util.List;

public class ListSerializer extends StdSerializer<List> {

public ListSerializer() {
    super(List.class);
}

@Override
public void serialize(List aList, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {

    if (aList != null) {

        jsonGenerator.writeStartObject();

        for (int index = 0 ; index < aList.size(); index++) {

            try {

                Object next = aList.get(index);

                List<Field> fields = FieldUtils.getAllFieldsList(next.getClass());

                Object object = next.getClass().newInstance();

                for (int j = 0 ; j < fields.size(); j ++ ) {

                    jsonGenerator.writeObjectField(String.format("%s[%s]",fields.get(j).getName(),index) , object);
                }

            } catch (Exception e) {
                e.printStackTrace();
            }

        }
        jsonGenerator.writeEndObject();
    }
}
}

Any ideas or alternatives for writing this ?