A gradle plugin for getting java lambda support in java 6, 7 and android
This plugin will automatically build your java or android project with retrolambda, giving you lambda goodness on java 6 or 7. It relies on the wonderful retrolambda by Esko Luontola.
Note: The minimum android gradle plugin is
1.5.0and the minimum gradle plugin is
2.5.
Download jdk8 and set it as your default.
Add the following to your build.gradle
buildscript { repositories { mavenCentral() }dependencies { classpath 'me.tatarka:gradle-retrolambda:3.7.1' }
}
// Required because retrolambda is on maven central repositories { mavenCentral() }
apply plugin: 'com.android.application' //or apply plugin: 'java' apply plugin: 'me.tatarka.retrolambda'
alternatively, you can use the new plugin syntax for gradle
2.1+
groovy plugins { id "me.tatarka.retrolambda" version "3.7.1" }
The plugin will compile the source code with java8 and then replace the class files with the output of retrolambda.
You can add a block like the following to configure the plugin:
groovy retrolambda { javaVersion JavaVersion.VERSION_1_6 jvmArgs '-arg1', '-arg2' defaultMethods false incremental true }
javaVersionSet the java version to compile to. The default is 6. Only 5, 6 or 7 are accepted.
include 'Debug', 'Release'Sets which sets/variants to run through retrolambda. The default is all of them.
exclude 'Test'Sets which sets/variants to not run through retrolambda. Only one of either
includeor
excludeshould be defined.
jvmArgsAdd additional jvm args when running retrolambda.
defaultMethodsTurn on default and static methods in interfaces support. Note: due to a limitation in retrolamba, this will set
incrementalto false. The default is false.
incrementalSetting this to false forces all of your class files to be run through retrolambda instead of only the ones that have changed. The default is true.
The default version of retrolambda used is
'net.orfjackal.retrolambda:retrolambda:2.5.6'. If you want to use a different one, you can configure it in your dependencies.
dependencies { // Latest one on maven central retrolambdaConfig 'net.orfjackal.retrolambda:retrolambda:+' // Or a local version // retrolambdaConfig files('libs/retrolambda.jar') }
If you are running with java 6 or 7 you should really consider updating. However, you may use the below configuration instead.
Set the environment variable
JAVA8_HOMEto point to the java 8 jdk. Alternatively, you can set the
jdkproperty.
groovy retrolambda { jdk System.getenv("JAVA8_HOME") }
You can force unit tests to be run with an older version of java by setting
JAVA5_HOME/
JAVA6_HOME/
JAVA7_HOMEor with the
oldJdkproperty.
groovy retrolambda { oldJdk System.getenv("JAVA6_HOME") }
Add these lines to your
build.gradleto inform the IDE of the language level.
android { compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 targetCompatibility JavaVersion.VERSION_1_8 } }
This plugin is fully compatible with proguard (since
v2.4.0). In your proguard file, add
-dontwarn java.lang.invoke.* -dontwarn **$$Lambda$*
First try updating to the latest version of the android gradle plugin. Newer versions of lint are compatible with java 8 sources. If you can't for some reason, you can still use the experimental fork to fix the issue.
Version
5.0.77contains bytecode that is incompatible with retrolambda. This should be fixed in newer versions of play services, if you can update, that should be the preferred solution. To work around this issue, you can either use an earlier version like
4.4.52or add
-noverifyto the jvm args. See orfjackal/retrolambda#25 for more information.
retrolambda { jvmArgs '-noverify' }
All updates have moved to the CHANGELOG.
Copyright 2013 Evan TatarkaLicensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.