Forgot to update api to latest version.

Replaced deprecated << operator with doLast.

demo_gradle/api/build.gradle

@@ -1,5 +1,5 @@
 dependencies {
-  compile 'ro.fortsoft.pf4j:pf4j:0.4'
+  compile 'ro.fortsoft.pf4j:pf4j:1.1.1'
   compile 'org.apache.commons:commons-lang3:3.0'
   testCompile group: 'junit', name: 'junit', version: '4.+'
 }

demo_gradle/build.gradle

@@ -7,7 +7,8 @@ subprojects {
   }
 }
 
-task copyPlugins() << {
+task copyPlugins() {
+    doLast {
         delete 'app/plugins'
         mkdir 'app/plugins'
 
@@ -22,3 +23,4 @@ task copyPlugins() << {
             }
         }
     }
+}