downgdading ecj compiler to version 4.4.2, the latest one compiled with target bytecode 1.6

.idea/libraries/Eclipse.xml

@@ -1,7 +1,7 @@
 <component name="libraryTable">
   <library name="Eclipse">
     <CLASSES>
-      <root url="jar://$PROJECT_DIR$/lib/ecj-4.5.1.jar!/" />
+      <root url="jar://$PROJECT_DIR$/lib/ecj-4.4.2.jar!/" />
     </CLASSES>
     <JAVADOC />
     <SOURCES />

lib/required_for_dist.txt

@@ -16,7 +16,7 @@ httpcore-4.4.1.jar
 httpclient-4.4.1.jar
 fluent-hc-4.4.1.jar
 httpmime-4.4.1.jar
-ecj-4.5.1.jar
+ecj-4.4.2.jar
 groovy-all-2.3.9.jar
 gson-2.3.1.jar
 guava-17.0.jar