java - IllegalArgumentException: Invalid boolean value when injecting property to boolean in Spring -

in spring boot attempt inject boolean value instance variable enviroment property set (enabled=true).

@value("${enabled}") private boolean enabled; 

however spring cannot resolve reason , reports:

caused by: java.lang.illegalargumentexception: invalid boolean value [${enabled}] 

it seems not replace expression ${enabled} property value.

what needs set ? why doesn't work default ?

as mentioned in comments, missing propertysourcesplaceholderconfigurer bean definition. here's example of how configure within java:

@configuration public class propertyconfig {      private static final string property_filename = "app.properties"; // change needed.         /**      * instance necessary spring load property file , allow access      * through @value(${propertyname}) annotation. note bean must static      * in order work current spring behavior.      */     @bean     public static propertysourcesplaceholderconfigurer properties() {         propertysourcesplaceholderconfigurer pspc = new propertysourcesplaceholderconfigurer();         resource[] resources = new classpathresource[] { new classpathresource(property_filename) };         pspc.setlocations(resources);         pspc.setignoreunresolvableplaceholders(true);         return pspc;     } }