Can I "use" Java 8 with Android Development now?

Question

I currently have Java 7 JDK installed. It's been like that for awhile. However, recently, my professor is instructing the class to uninstall Java JDK 7 and install Java JDK 8 instead to be able to work on homework and such.

I've been using Java JDK 7 to write and deploy Android apps without any problems so I'm wondering if it's safe to make the upgrade now the JDK 8? I'm assuming that I won't be needing any Java 8 specific methods or functions in my Android development. So if I stay away from that, will my Android development be at all affected?

On a side note, I haven't been able to find any official documentation that states whether or not Java JDK 8 is safe or not or how to make it safe. Either way, I'm going to have to upgrade to Java 8 soon...

Answer 1

In Google I/O 2016, they announced that Android now supports some features of Java 8, but not all the features.

Features like

• Default and static interface methods
• Lambda expressions (also available on API level 23 and lower)
• Repeatable annotations
• Method References (also available on API level 23 and lower)
• Type Annotations (also available on API level 23 and lower)

Additionally, the following Java 8 language APIs are also available:

• Reflection and language-related APIs
  • java.lang.FunctionalInterface
  • java.lang.annotation.Repeatable
  • java.lang.reflect.Method.isDefault()
  • and Reflection APIs associated with repeatable annotations, such as AnnotatedElement.getAnnotationsByType(Class)
• Utility APIs
  • java.util.function
  • java.util.stream

All what you should do is to use the new jack compiler, to do this you have just to add this to your gradle file build.gradle (Module: app):

android {
  ...
  defaultConfig {
    ...
    jackOptions {
      enabled true
    }
  }
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

References:

• https://developer.android.com/guide/platform/j8-jack.html
• https://www.youtube.com/watch?v=B08iLAtS3AQ&feature=youtu.be&t=28m14s