Update readme

Author: HosseinYousefi

pkgs/jni/README.md

@@ -21,3 +21,13 @@ Apart from being the base library for code generated by `jnigen` this can also b
 The test/ directory contains files with comments explaining the basics of this module, and the example/ directory contains a flutter example which also touches some Android-specifics.
 
 Using this library assumes some familiarity with JNI - it's threading model and object references, among other things.
+
+## Migrating to 0.8.0
+
+Check the [changelog](https://github.com/dart-lang/native/blob/main/pkgs/jni/CHANGELOG.md#080-wip).
+
+The API for standalone use of `package:jni` (without `package:jnigen`) has
+changed to use `JClass.forName` for finding classes. Find the methods and fields
+by accessing them from the retrieved `JClass`. For example find an instance
+method with a name and a signature using `jClass.instanceMethodId`. Then you can
+`call` the resulting `JInstanceMethodId` to call the instance method.

pkgs/jnigen/CHANGELOG.md

@@ -1,5 +1,10 @@
 ## 0.8.0-wip
 
+- **Breaking Change** ([#981](https://github.com/dart-lang/native/issues/981)):
+  - `fromRef` is now `fromReference`, and it gets a `JReference` instead of a
+    `Pointer<Void>`.
+  - Check out the internal changes to `JObject` in
+    [`package:jni`'s changelog](https://github.com/dart-lang/native/blob/main/pkgs/jni/CHANGELOG.md#080-wip).
 - **Breaking Change**: The generated impl class for interfaces is now an
   `interface`.
 - **Breaking Change** ([#792](https://github.com/dart-lang/native/issues/792)]):

pkgs/jnigen/README.md

@@ -282,6 +282,10 @@ However there are 2 caveats to this caveat.
 
 The JAR files (`$SDK_ROOT/platforms/android-$VERSION/android.jar`) can be used instead. But compiled JARs do not include JavaDoc and method parameter names. This JAR is automatically included by Gradle when `android_sdk_config` >> `add_gradle_deps` is specified.
 
+## Migrating to 0.8.0
+
+Check [`jni`'s changelog](https://github.com/dart-lang/native/blob/main/pkgs/jni/CHANGELOG.md#080-wip) and [`jnigen`'s changelog](https://github.com/dart-lang/native/blob/main/pkgs/jnigen/CHANGELOG.md#080-wip).
+
 ## Contributing
 See the wiki for architecture-related documents.