Register Spring Converter Programmatically in Spring Boot
<p>I want to register a Spring Converter in a Spring Boot project programmatically. In past Spring projects I've done it in XML like this... </p>

<pre><code>&lt;!-- Custom converters to allow automatic binding from Http requests parameters to objects --&gt;
&lt;!-- All converters are annotated w/@Component --&gt;
&lt;bean id="conversionService"
      class="org.springframework.context.support.ConversionServiceFactoryBean"&gt;
    &lt;property name="converters"&gt;
        &lt;list&gt;
            &lt;ref bean="stringToAssessmentConverter" /&gt;
        &lt;/list&gt;
    &lt;/property&gt;
&lt;/bean&gt;
</code></pre>

<p>I'm trying to figure out how to do in Spring Boot's SpringBootServletInitializer</p>

<p><strong>Update:</strong> I've made a little progress by passing the StringToAssessmentConverter as an argument to <code>getConversionService</code>, but now I'm getting a <code>"No default constructor found"</code> error for the StringToAssessmentConverter class. I'm not sure why Spring is not seeing the @Autowired constructor.</p>

<pre><code>@SpringBootApplication
public class Application extends SpringBootServletInitializer {

    ...

    @Bean(name="conversionService")
    public ConversionServiceFactoryBean getConversionService(StringToAssessmentConverter stringToAssessmentConverter) {
        ConversionServiceFactoryBean bean = new ConversionServiceFactoryBean();

        Set&lt;Converter&gt; converters = new HashSet&lt;&gt;();

        converters.add(stringToAssessmentConverter);

        bean.setConverters(converters);
        return bean;
    }
}  
</code></pre>

<p>Here's the code for the Converter... </p>

<pre><code> @Component
 public class StringToAssessmentConverter implements Converter&lt;String, Assessment&gt; {

     private AssessmentService assessmentService;

     @Autowired
     public StringToAssessmentConverter(AssessmentService assessmentService) {
         this.assessmentService = assessmentService;
     }

     public Assessment convert(String source) {
         Long id = Long.valueOf(source);
         try {
             return assessmentService.find(id);
         } catch (SecurityException ex) {
             return null;
         }
     }
 }
</code></pre>

<p>Full Error</p>

<pre><code>Failed to execute goal org.springframework.boot:spring-boot-maven-
plugin:1.3.2.RELEASE:run (default-cli) on project yrdstick: An exception 
occurred while running. null: InvocationTargetException: Error creating 
bean with name
'org.springframework.boot.context.properties.ConfigurationPropertiesBindingPo
stProcessor': Invocation of init method failed; nested exception is 
org.springframework.beans.factory.UnsatisfiedDependencyException: Error 
creating bean with name 'conversionService' defined in 
me.jpolete.yrdstick.Application: Unsatisfied dependency expressed through 
constructor argument with index 0 of type 
[me.jpolete.yrdstick.websupport.StringToAssessmentConverter]: : Error 
creating bean with name 'stringToAssessmentConverter' defined in file 
[/yrdstick/target/classes/me/jpolete/yrdstick/websupport
/StringToAssessmentConverter.class]: Instantiation of bean failed; nested 
exception is org.springframework.beans.BeanInstantiationException: Failed 
to instantiate 
[me.jpolete.yrdstick.websupport.StringToAssessmentConverter]: No default 
constructor found; nested exception is java.lang.NoSuchMethodException: 
me.jpolete.yrdstick.websupport.StringToAssessmentConverter.&lt;init&gt;(); 
nested exception is 
org.springframework.beans.factory.BeanCreationException: Error creating 
bean with name 'stringToAssessmentConverter' defined in file [/yrdstick
/dev/yrdstick/target/classes/me/jpolete/yrdstick/websupport
/StringToAssessmentConverter.class]: Instantiation of bean failed; nested 
exception is org.springframework.beans.BeanInstantiationException: Failed 
to instantiate 
[me.jpolete.yrdstick.websupport.StringToAssessmentConverter]: No default 
constructor found; nested exception is java.lang.NoSuchMethodException: 
me.jpolete.yrdstick.websupport.StringToAssessmentConverter.&lt;init&gt;()
</code></pre>