adding Retrolambda

app/build.gradle

@@ -1,4 +1,5 @@
 apply plugin: 'com.android.application'
+apply plugin: 'me.tatarka.retrolambda'
 
 android {
     compileSdkVersion 25
@@ -23,7 +24,13 @@ android {
         exclude 'META-INF/NOTICE'
         exclude 'META-INF/notice.txt'
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 }
+
+
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     compile 'com.android.support:leanback-v17:25.3.0'

build.gradle

@@ -3,9 +3,11 @@
 buildscript {
     repositories {
         jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.3.0'
+        classpath 'me.tatarka:gradle-retrolambda:3.6.0'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
@@ -21,4 +23,4 @@ allprojects {
 
 task clean(type: Delete) {
     delete rootProject.buildDir
-}
+}