Does Spring MessageSource Support Multiple Class Path?

The issue here is not with multiple classpaths or classloaders, but with how many resources the code will try and load for a given path.

The classpath* syntax is a Spring mechanism, one which allows code to load multiple resources for a given path. Very handy. However, ResourceBundleMessageSource uses the standard java.util.ResourceBundle to load the resources, and this is a much simpler, dumber mechanism, which will load the first resource for a given path, and ignore everything else.

I don't really have an easy fix for you. I think you're going to have to ditch ResourceBundleMessageSource and write a custom implementation of MessageSource (most likely by subclassing AbstractMessageSource) which uses PathMatchingResourcePatternResolver to locate the various resources and expose them via the MessageSource interface. ResourceBundle isn't going to be much help.

With the solution of @seralex-vi basenames /WEB-INF/messages did not function.

I overwrited the method refreshProperties on the class ReloadableResourceBundleMessageSource wich perform both type of basenames (classpath*: and /WEB-INF/)

public class SmReloadableResourceBundleMessageSource extends ReloadableResourceBundleMessageSource {

private static final String PROPERTIES_SUFFIX = ".properties";

private PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();

@Override
protected PropertiesHolder refreshProperties(String filename, PropertiesHolder propHolder) {
    if (filename.startsWith(PathMatchingResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX)) {
        return refreshClassPathProperties(filename, propHolder);
    } else {
        return super.refreshProperties(filename, propHolder);
    }
}

private PropertiesHolder refreshClassPathProperties(String filename, PropertiesHolder propHolder) {
    Properties properties = new Properties();
    long lastModified = -1;
    try {
      Resource[] resources = resolver.getResources(filename + PROPERTIES_SUFFIX);
      for (Resource resource : resources) {
        String sourcePath = resource.getURI().toString().replace(PROPERTIES_SUFFIX, "");
        PropertiesHolder holder = super.refreshProperties(sourcePath, propHolder);
        properties.putAll(holder.getProperties());
        if (lastModified < resource.lastModified())
          lastModified = resource.lastModified();
      }
    } catch (IOException ignored) { 
    }
    return new PropertiesHolder(properties, lastModified);
}

On the spring-context.xml you must have the classpath*: prefix

<bean id="messageSource" class="SmReloadableResourceBundleMessageSource">
    <property name="basenames">
        <list>
            <value>/WEB-INF/i18n/enums</value>
            <value>/WEB-INF/i18n/messages</value>
            <value>classpath*:/META-INF/messages-common</value>
            <value>classpath*:/META-INF/enums</value>
        </list>
    </property>
</bean>