title: PropertySourcesPlaceholderConfigurer and PropertyPlaceholderConfigurer
body: <p>I made an analysis of a legacy code (it's Spring application) and found both <code>PropertySourcesPlaceholderConfigurer</code> and <code>PropertyPlaceholderConfigurer</code> initialized in Spring context. I know that only one instance of <code>PropertyPlaceholderConfigurer</code> should exist in Spring context. My question is if this rule is the same applying to <code>PropertySourcesPlaceholderConfigurer</code> and <code>PropertyPlaceholderConfigurer</code>. Is it a mistake to have both of them into context?</p>