Migrate from jack to native Java 8

Question

I am trying to use lambda expressions and threads in my Android project. I use streamsupport library for streams, and native Java 8 for lambda expressions. To be able to use Java 8 features I need to add

compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 targetCompatibility JavaVersion.VERSION_1_8 } 

this code is in my gradle, but the compiler shows this error:

 Error:Jack is required to support java 8 language features. Either enable Jack or remove sourceCompatibility JavaVersion.VERSION_1_8. 

and then I added this

 jackOptions { enabled true } 

and the compiler was not mistaken, but at runtime the same error continues to be displayed. This is my gradle

 apply plugin: 'com.android.application' android { compileSdkVersion 25 buildToolsVersion "25.0.3" defaultConfig { applicationId "home.gio.calorieplanner" minSdkVersion 16 targetSdkVersion 25 versionCode 1 versionName "1.0" testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" multiDexEnabled true } compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 targetCompatibility JavaVersion.VERSION_1_8 } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } } dependencies { compile fileTree(include: ['*.jar'], dir: 'libs') androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { exclude group: 'com.android.support', module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:25.3.1' compile 'com.android.support:recyclerview-v7:25.3.1' compile 'com.android.support.constraint:constraint-layout:1.0.2' compile 'com.android.support:support-v4:25.3.1' compile 'org.greenrobot:eventbus:3.0.0' compile 'com.android.support:design:25.3.1' compile 'com.google.firebase:firebase-crash:10.0.1' compile 'com.google.code.gson:gson:2.8.0' compile 'com.google.firebase:firebase-database:10.2.4' compile 'com.google.firebase:firebase-core:10.2.4' compile 'com.jakewharton:butterknife:8.5.1' compile 'com.firebaseui:firebase-ui-database:1.1.0' compile 'org.jsoup:jsoup:1.10.2' compile 'com.android.support:percent:25.3.1' compile 'com.thoughtbot:expandablecheckrecyclerview:1.4' testCompile 'junit:junit:4.12' annotationProcessor 'com.jakewharton:butterknife-compiler:8.5.1' compile 'net.sourceforge.streamsupport:streamsupport:1.5.4' } apply plugin: 'com.google.gms.google-services' 

and this is a method in which I use lambda expressions and threads.

 public String identifySubMenu(String group, int index) { List<Product> prod = StreamSupport .stream(Main.outRetailChainList.get(Constants.GOODWILL).getProducts()) .filter(item -> item.getCategory().equals(group)) .collect(Collectors.toList()); return prod.get(index).getSubMenu(); } 

So my question is how can I fix this error.

Answer 1

You have many options:

1 - upgrade the version of Android-studio to version 3.0, these versions no longer need a socket, and lambda is now correctly processed, but this version is in the channel channel, that is, in their "beta version".

2 - do not use lambda now and wait 3.0 to free it, as the socket does not fully process lambda. You got a fully explained page: https://developer.android.com/guide/platform/j8-jack.html

3 - use a plugin called retrolambda , but this will increase compilation time. In my opinion, this option is too heavy just for lambda