anchor.diff:      public class AppConfig {
   
            @Bean
  -         public PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
  +         public static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
                  return new PropertySourcesPlaceholderConfigurer();
            }
       }
   ----
   
  -Using the above configuration ensures Spring initialization failure if any of `${}`
  +NOTE: When configuring a `PropertySourcesPlaceholderConfigurer` using JavaConfig, the
  +`@Bean` method must be `static`.
  +
  +Using the above configuration ensures Spring initialization failure if any `${}`
   placeholder could not be resolved. It is also possible to use methods like
  -`setPlaceholderPrefix`, `setPlaceholderSuffix` or `setValueSeparator` to customize placeholders.
  +`setPlaceholderPrefix`, `setPlaceholderSuffix`, or `setValueSeparator` to customize
  +placeholders.
   
   NOTE: Spring Boot configures by default a `PropertySourcesPlaceholderConfigurer` bean that
   will get properties from `application.properties` and `application.yml` files.
   
   Built-in converter support provided by Spring allows simple type conversion (to `Integer`
  -or `int` for example) to be automatically handled. Multiple comma separated values parameter
  -can be automatically converted to String array without extra effort.
  +or `int` for example) to be automatically handled. Multiple comma-separated values can be
  +automatically converted to String array without extra effort.
   
   It is possible to provide a default value as following:
   
  
positive.code:     }
  ----
  
  <<expressions, `SpEL` expression>> built-in support allows dynamically computed `@Value`
  at runtime as in the following example shows:
  
  [source,java,indent=0]
  [subs="verbatim,quotes"]
  
negative.code: 
  A default lenient embedded value resolver is provided by Spring. It will try to resolve the
  property value and if it cannot be resolved, the property name (for example `${catalog.name}`)
  will be injected as the value. If you want to maintain strict control over nonexistent
  values, you should declare a `PropertySourcesPlaceholderConfigurer` bean, as the following
  example shows:
  
  