Often there are Spring-related configuration options which don't belong inside the final jar/war for a Java application. Either because the options are different for each deployment environment or because the value of the option is sensitive ( passwords ). The PropertyPlaceholderConfigurer class attempts to remedy the management and injection of the values for these options. It reads one or more property files, optionally using system properties for defaults, and uses the values found to fill property placeholders of the form ${property name} found in the ApplicationContext in which the configurer is defined.