- * A {@link #value()} can be safely specified on {@code @Configuration} classes as the - * annotation metadata is parsed by using ASM before the class is loaded. Extra care is - * required when placed on {@code @Bean} methods, consider isolating the condition in a - * separate {@code Configuration} class, in particular if the return type of the method - * matches the {@link #value target of the condition}. + * A {@code Class} {@link #value() value} can be safely specified on + * {@code @Configuration} classes as the annotation metadata is parsed by using ASM before + * the class is loaded. If a class reference cannot be used then a {@link #name() name} + * {@code String} attribute can be used. + *
+ * Note: Extra care must be taken when using {@code @ConditionalOnClass} on + * {@code @Bean} methods where typically the return type is the target of the condition. + * Before the condition on the method applies, the JVM will have loaded the class and + * potentially processed method references which will fail if the class is not present. To + * handle this scenario, a separate {@code @Configuration} class should be used to isolate + * the condition. For example:
+ * @Configuration(proxyBeanMethods = false)
+ * public class MyAutoConfiguration {
+ *
+ * @Configuration(proxyBeanMethods = false)
+ * @ConditionalOnClass(SomeService.class)
+ * public static class SomeServiceConfiguration {
+ *
+ * @Bean
+ * @ConditionalOnMissingBean
+ * public SomeService someService() {
+ * return new SomeService();
+ * }
+ *
+ * }
+ *
+ * }
*
* @author Phillip Webb
* @since 1.0.0