Starting with version 2.3 this plugin uses the Maven Filtering shared component for filtering resources. By default maven resource filtering is not enabled. These variables, denoted by the ${...} delimiters, can come from the system properties, your project properties, from your filter resources and from the command line.. For example, if we have a resource src/main/resources/hello.txt containing Variables can be included in your resources. The three variations below only differ in how the resource and output directory elements are specified or defaulted. Goals. The Resources Plugin copies files specified by Resource elements, to an output directory. In that case @..@ delimiter is used instead of ${}, that is to avoid conflict with the spring-style placeholder ${}. These variables, denoted by the ${...} delimiters, can come from the system properties, your project properties, from your filter resources and from the command line.. For example, if we have a resource src/main/resources/hello.txt containing Filtering. When resource filtering is activated, Maven will scan resources for property references surrounded by ${and }. When it finds these references it will replace them with the appropriate value in much the same way the properties defined in the previous section can be referenced from a POM. Variables can be included in your resources. Filtering. If we extend our Spring Boot project from spring-boot-starter-parent the resource filtering is enabled by default.