Demo :: Java8 in android with jack compiler

build.gradle

android {
  compileSdkVersion 'android-N'
  buildToolsVersion "24.0.0-rc3"

  defaultConfig {
      applicationId "up1.demoandroidn"
      minSdkVersion 24
      targetSdkVersion 24
      versionCode 1
      versionName "1.0"
      jackOptions{
          enabled true
      }
  }

  compileOptions {
      targetCompatibility 1.8
      sourceCompatibility 1.8
  }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button clickMeButton = (Button) findViewById(R.id.clickMeButton);
        clickMeButton.setOnClickListener(view -> {
            makeText(MainActivity.this, "Hello", Toast.LENGTH_LONG).show();
        }
        );

    }
}

Money.java

public interface Money {
    void setMoney(BigDecimal money);
    BigDecimal getMoney();
    String getCurentcy();

    default String getFormattedMoney() {
        return String.format(Locale.getDefault(),
                "Money is %.3f %s", getMoney().floatValue(), getCurentcy());
    }
}