Is my class a bean?

For almost every Java class that we as developers have ever written, the answer would be yes, most definitely, as long as the Java class has either a constructor with no parameters or a constructor that is annotated with @Inject.

There is only one requirement that CDI mandates for a Java class to be injected as a bean, and that's for the Java class to be packaged into an appropriate archive (such as a JAR or WAR) that contains a descriptor file called beans.xml. This descriptor file needs to be present in the META-INF folder of a JAR or the WEB-INF folder of a WAR.

It's perfectly fine for beans.xml to be completely empty or only contain the following XML content:

<beans xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="
    http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
</beans>

For most applications, the sole purpose of beans.xml is to notify CDI that there are beans within the archive that need to be scanned, so that they are available to have beans injected into them as well as be injected into other beans that may not be present within this archive.