Deconstructed APK prototyping

apk/hijack/org/chromium/deconstructed/ApplicationInstaller.java

+package org.chromium.deconstructed;
+
+import android.app.Application;
+
+import java.lang.ref.WeakReference;
+import java.lang.reflect.InvocationTargetException;
+import java.util.List;
+import java.util.Map;
+
+public class ApplicationInstaller {
+    public static void install(Application currentApplication, Application realApplication)
+            throws ClassNotFoundException, InvocationTargetException, NoSuchFieldException,
+                   NoSuchMethodException {
+        Object currentActivityThread =
+                Reflect.invokeStaticMethod("android.app.ActivityThread", "currentActivityThread");
+        if (Reflect.getField(currentActivityThread, "mInitialApplication") == currentApplication) {
+            Reflect.setField(currentActivityThread, "mInitialApplication", realApplication);
+        }
+
+        List<Application> allApplications =
+                (List<Application>) Reflect.getField(currentActivityThread, "mAllApplications");
+        for (int i = 0; i < allApplications.size(); i++) {
+            if (allApplications.get(i) == currentApplication) {
+                allApplications.set(i, realApplication);
+            }
+        }
+
+        for (String fieldName : new String[] {"mPackages", "mResourcePackages"}) {
+            Map<String, WeakReference<?>> packageMap =
+                    (Map<String, WeakReference<?>>) Reflect.getField(
+                            currentActivityThread, fieldName);
+            for (Map.Entry<String, WeakReference<?>> entry : packageMap.entrySet()) {
+                Object loadedApk = entry.getValue().get();
+                if (loadedApk == null) continue;
+                if (Reflect.getField(loadedApk, "mApplication") == currentApplication) {
+                    Reflect.setField(loadedApk, "mApplication", realApplication);
+                    Reflect.setField(realApplication, "mLoadedApk", loadedApk);
+                }
+            }
+        }
+    }
+}