title: Cannot invoke method version() on null object
body: <p>i'm trying to use the Jgrapht library but it needs lambdas...</p>
  
  <p>Here's my code:</p>
  
  <pre><code>    // Top-level build file where you can add configuration options common to all sub-projects/modules.
  
  buildscript {
      repositories {
          maven {
              url "https://plugins.gradle.org/m2/"
          }
          jcenter()
      }
      dependencies {
          classpath "gradle.plugin.me.tatarka:gradle-retrolambda:3.3.0"
          classpath 'com.android.tools.build:gradle:2.2.1'
      }
  }
  allprojects {
      repositories {
          jcenter()
          mavenCentral()
      }
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  </code></pre>
  
  <p>And the :app</p>
  
  <pre><code>apply plugin: "me.tatarka.retrolambda" version "3.3.0"
  apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 23
      buildToolsVersion "24.0.3"
      compileOptions {
          sourceCompatibility JavaVersion.VERSION_1_8
          targetCompatibility JavaVersion.VERSION_1_8
      }
  
      defaultConfig {
          applicationId "it.univpm.gruppoids.iotforemergencyandnavigation"
          minSdkVersion 16
          targetSdkVersion 23
          versionCode 1
          versionName "1.0"
  
         jackOptions {
              enabled true
          }
      }
  
  
  
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
  }
  dependencies {
      compile fileTree(include: ['*.jar'], dir: 'libs')
      testCompile 'junit:junit:4.12'
      compile 'com.android.support:appcompat-v7:23.4.0'
      compile 'com.android.support:design:23.4.0'
      compile 'com.android.support:support-v4:23.4.0'
      compile 'com.journeyapps:zxing-android-embedded:3.2.0@aar'
      compile 'com.google.zxing:core:3.2.1'
      compile 'org.jgrapht:jgrapht-core:1.0.0'
  }
  </code></pre>
  
  <p>The error is: Error:(1, 0) Cannot invoke method version() on null object
  Open File
  Where and what is the error? thanks</p>