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

@@ -7,18 +7,20 @@ subprojects {
   }
 }
 
-task copyPlugins() << {
-  delete 'app/plugins'
-  mkdir 'app/plugins'
+task copyPlugins() {
+    doLast {
+        delete 'app/plugins'
+        mkdir 'app/plugins'
 
-  subprojects.each { p ->
-    if (p.path.contains(":plugins/")) {
-      System.out.println("Copying plugin from " +  p.path);
-      copy {
-        from p.projectDir.toString() + '/build/libs'
-        into 'app/plugins'
-        include '*.zip'
-      }
+        subprojects.each { p ->
+            if (p.path.contains(":plugins/")) {
+                System.out.println("Copying plugin from " +  p.path);
+                copy {
+                    from p.projectDir.toString() + '/build/libs'
+                    into 'app/plugins'
+                    include '*.zip'
+                }
+            }
+        }
     }
-  }
 }