Camel processor not autowiring Spring bean

Question

Not really sure why this isn't working - I've tested the CustomerService autowiring outside of the camel route (HelloCamelClient) and it works fine, but once I put it in a camel Processor class, it does not autowire correctly. It gets as far as cs.getCustomer() in the process() function, then throws a NullPointerException.

Camel Context XML

    <camelContext trace="false" xmlns="http://camel.apache.org/schema/spring">
    <route id="HelloWorldRoute">
        <from uri="jetty:http://0.0.0.0:8888/hellocamel"/>
        <transform>
            <language language="simple">Hello ${body}</language>
        </transform>
    </route>
    <route id="HelloWorldRoute2">
        <from uri="jetty:http://0.0.0.0:8888/hellocamel2"/>
        <to uri="bean:myProcessor"/>
    </route>
</camelContext> 

<bean id="myProcessor" class="com.fusesource.byexample.hellocamel.impl.CamelHandler"/>
<bean id="customerService" class="com.fusesource.byexample.hellocamel.impl.CustomerService2" />
<bean id="HelloCamelClient" class="com.fusesource.byexample.hellocamel.impl.HelloCamelClient" />

CamelHandler.java

package com.fusesource.byexample.hellocamel.impl;

import java.sql.SQLException;

import javax.sql.DataSource;

import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.fusesource.byexample.hellocamel.impl.CustomerService2;

@Service
public class CamelHandler implements Processor {

    @Autowired 
    private CustomerService2 cs;

    public CamelHandler() {
        // 
    }

    public void test() throws SQLException {

    }

    @Override
    public void process(Exchange arg0) throws Exception {

        cs.getCustomer();
        arg0.getOut().setBody(cs.getCustomer());
    }


}

Answer 1

I changed my code to have setter methods for DataSource and CustomerService, and it seems to work fine now. Not sure why though.

2018 AND NOT A NOOB ANYMORE UPDATE: This is because with an empty constructor provided, Spring only has the ability to use that to build the bean, and can't possibly set any @Autowired fields. Adding setters gave Spring the ability to populate those fields. The (preferred) alternative is to use Constructor Injection instead of the @Autowired annotation.