Issue 4248 - Add codestyle check

libadblockplus-android/build.gradle

 apply plugin: 'com.android.library'
+apply plugin: 'checkstyle'
 
 android {
-  compileSdkVersion 16
-  buildToolsVersion "25.0.0"
+    compileSdkVersion 16
+    buildToolsVersion "25.0.0"
 
-  defaultConfig {
-    minSdkVersion 11
-    targetSdkVersion 16
-    versionCode 1
-    versionName "1.0"
+    defaultConfig {
+        minSdkVersion 11
+        targetSdkVersion 16
+        versionCode 1
+        versionName "1.0"
 
-    ndk {
-      abiFilters 'armeabi-v7a', 'x86'
+        ndk {
+            abiFilters 'armeabi-v7a', 'x86'
+        }
     }
-  }
 
-  externalNativeBuild {
-    ndkBuild {
-      path 'jni/Android.mk'
+    externalNativeBuild {
+        ndkBuild {
+            path 'jni/Android.mk'
+        }
     }
-  }
 
-  sourceSets {
-    main {
-      manifest.srcFile 'AndroidManifest.xml'
-      java.srcDirs = ['src']
-      res.srcDirs = ['res']
-      jni.srcDirs = ['jni']
+    sourceSets {
+        main {
+            manifest.srcFile 'AndroidManifest.xml'
+            java.srcDirs = ['src']
+            res.srcDirs = ['res']
+            jni.srcDirs = ['jni']
+        }
     }
-  }
+}
+
+checkstyle {
+    toolVersion = '6.19'
+}
+
+task checkstyleMain(type: Checkstyle) {
+    ignoreFailures = true
+    showViolations = true
+    source 'src/org/adblockplus/'
+    exclude '**/gen/**'
+    exclude '**/R.java'
+    exclude '**/BuildConfig.java'
+    reports {
+        xml.destination "$project.buildDir/reports/checkstyle/main.xml"
+    }
+    classpath = files()
+    configFile = file("${rootProject.rootDir}/third_party/checkstyle/java/rules/eyeo_production_checks.xml")
+    configProperties = [
+        "checkstyle.header.file" : file("${rootProject.rootDir}/third_party/checkstyle/java/res/header.txt")
+    ]
 }