diff --git a/updater_sample/Android.mk b/updater_sample/Android.mk
index 2786de4..056ad66 100644
--- a/updater_sample/Android.mk
+++ b/updater_sample/Android.mk
@@ -26,6 +26,10 @@
 
 LOCAL_SRC_FILES := $(call all-java-files-under, src)
 
+LOCAL_STATIC_JAVA_LIBRARIES += guava
+
+LOCAL_RESOURCE_DIR := $(LOCAL_PATH)/res
+
 include $(BUILD_PACKAGE)
 
 # Use the following include to make our test apk.
diff --git a/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java b/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
index cbee18f..23510e4 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
@@ -19,6 +19,7 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
@@ -26,13 +27,13 @@
 import java.io.Serializable;
 
 /**
- * UpdateConfig describes an update. It will be parsed from JSON, which is intended to
+ * An update description. It will be parsed from JSON, which is intended to
  * be sent from server to the update app, but in this sample app it will be stored on the device.
  */
 public class UpdateConfig implements Parcelable {
 
-    public static final int TYPE_NON_STREAMING = 0;
-    public static final int TYPE_STREAMING     = 1;
+    public static final int AB_INSTALL_TYPE_NON_STREAMING = 0;
+    public static final int AB_INSTALL_TYPE_STREAMING = 1;
 
     public static final Parcelable.Creator<UpdateConfig> CREATOR =
             new Parcelable.Creator<UpdateConfig>() {
@@ -54,18 +55,30 @@
         JSONObject o = new JSONObject(json);
         c.mName = o.getString("name");
         c.mUrl = o.getString("url");
-        if (TYPE_NON_STREAMING_JSON.equals(o.getString("type"))) {
-            c.mInstallType = TYPE_NON_STREAMING;
-        } else if (TYPE_STREAMING_JSON.equals(o.getString("type"))) {
-            c.mInstallType = TYPE_STREAMING;
-        } else {
-            throw new JSONException("Invalid type, expected either "
-                    + "NON_STREAMING or STREAMING, got " + o.getString("type"));
+        switch (o.getString("ab_install_type")) {
+            case AB_INSTALL_TYPE_NON_STREAMING_JSON:
+                c.mAbInstallType = AB_INSTALL_TYPE_NON_STREAMING;
+                break;
+            case AB_INSTALL_TYPE_STREAMING_JSON:
+                c.mAbInstallType = AB_INSTALL_TYPE_STREAMING;
+                break;
+            default:
+                throw new JSONException("Invalid type, expected either "
+                        + "NON_STREAMING or STREAMING, got " + o.getString("ab_install_type"));
         }
-        if (o.has("metadata")) {
-            c.mMetadata = new Metadata(
-                    o.getJSONObject("metadata").getInt("offset"),
-                    o.getJSONObject("metadata").getInt("size"));
+        if (c.mAbInstallType == AB_INSTALL_TYPE_STREAMING) {
+            JSONObject meta = o.getJSONObject("ab_streaming_metadata");
+            JSONArray propertyFilesJson = meta.getJSONArray("property_files");
+            InnerFile[] propertyFiles =
+                new InnerFile[propertyFilesJson.length()];
+            for (int i = 0; i < propertyFilesJson.length(); i++) {
+                JSONObject p = propertyFilesJson.getJSONObject(i);
+                propertyFiles[i] = new InnerFile(
+                        p.getString("filename"),
+                        p.getLong("offset"),
+                        p.getLong("size"));
+            }
+            c.mAbStreamingMetadata = new StreamingMetadata(propertyFiles);
         }
         c.mRawJson = json;
         return c;
@@ -74,8 +87,8 @@
     /**
      * these strings are represent types in JSON config files
      */
-    private static final String TYPE_NON_STREAMING_JSON  = "NON_STREAMING";
-    private static final String TYPE_STREAMING_JSON      = "STREAMING";
+    private static final String AB_INSTALL_TYPE_NON_STREAMING_JSON = "NON_STREAMING";
+    private static final String AB_INSTALL_TYPE_STREAMING_JSON = "STREAMING";
 
     /** name will be visible on UI */
     private String mName;
@@ -84,10 +97,10 @@
     private String mUrl;
 
     /** non-streaming (first saves locally) OR streaming (on the fly) */
-    private int mInstallType;
+    private int mAbInstallType;
 
     /** metadata is required only for streaming update */
-    private Metadata mMetadata;
+    private StreamingMetadata mAbStreamingMetadata;
 
     private String mRawJson;
 
@@ -97,15 +110,15 @@
     protected UpdateConfig(Parcel in) {
         this.mName = in.readString();
         this.mUrl = in.readString();
-        this.mInstallType = in.readInt();
-        this.mMetadata = (Metadata) in.readSerializable();
+        this.mAbInstallType = in.readInt();
+        this.mAbStreamingMetadata = (StreamingMetadata) in.readSerializable();
         this.mRawJson = in.readString();
     }
 
     public UpdateConfig(String name, String url, int installType) {
         this.mName = name;
         this.mUrl = url;
-        this.mInstallType = installType;
+        this.mAbInstallType = installType;
     }
 
     public String getName() {
@@ -121,16 +134,18 @@
     }
 
     public int getInstallType() {
-        return mInstallType;
+        return mAbInstallType;
+    }
+
+    public StreamingMetadata getStreamingMetadata() {
+        return mAbStreamingMetadata;
     }
 
     /**
-     * "url" must be the file located on the device.
-     *
      * @return File object for given url
      */
     public File getUpdatePackageFile() {
-        if (mInstallType != TYPE_NON_STREAMING) {
+        if (mAbInstallType != AB_INSTALL_TYPE_NON_STREAMING) {
             throw new RuntimeException("Expected non-streaming install type");
         }
         if (!mUrl.startsWith("file://")) {
@@ -148,29 +163,60 @@
     public void writeToParcel(Parcel dest, int flags) {
         dest.writeString(mName);
         dest.writeString(mUrl);
-        dest.writeInt(mInstallType);
-        dest.writeSerializable(mMetadata);
+        dest.writeInt(mAbInstallType);
+        dest.writeSerializable(mAbStreamingMetadata);
         dest.writeString(mRawJson);
     }
 
     /**
-     * Metadata for STREAMING update
+     * Metadata for streaming A/B update.
      */
-    public static class Metadata implements Serializable {
+    public static class StreamingMetadata implements Serializable {
 
         private static final long serialVersionUID = 31042L;
 
         /** defines beginning of update data in archive */
+        private InnerFile[] mPropertyFiles;
+
+        public StreamingMetadata() {
+            mPropertyFiles = new InnerFile[0];
+        }
+
+        public StreamingMetadata(InnerFile[] propertyFiles) {
+            this.mPropertyFiles = propertyFiles;
+        }
+
+        public InnerFile[] getPropertyFiles() {
+            return mPropertyFiles;
+        }
+    }
+
+    /**
+     * Description of a file in an OTA package zip file.
+     */
+    public static class InnerFile implements Serializable {
+
+        private static final long serialVersionUID = 31043L;
+
+        /** filename in an archive */
+        private String mFilename;
+
+        /** defines beginning of update data in archive */
         private long mOffset;
 
         /** size of the update data in archive */
         private long mSize;
 
-        public Metadata(long offset, long size) {
+        public InnerFile(String filename, long offset, long size) {
+            this.mFilename = filename;
             this.mOffset = offset;
             this.mSize = size;
         }
 
+        public String getFilename() {
+            return mFilename;
+        }
+
         public long getOffset() {
             return mOffset;
         }
@@ -178,6 +224,7 @@
         public long getSize() {
             return mSize;
         }
+
     }
 
 }
diff --git a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
index 72e1b24..8507a9e 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
@@ -260,7 +260,7 @@
      * Applies the given update
      */
     private void applyUpdate(UpdateConfig config) {
-        if (config.getInstallType() == UpdateConfig.TYPE_NON_STREAMING) {
+        if (config.getInstallType() == UpdateConfig.AB_INSTALL_TYPE_NON_STREAMING) {
             AbNonStreamingUpdate update = new AbNonStreamingUpdate(mUpdateEngine, config);
             try {
                 update.execute();
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/FileDownloader.java b/updater_sample/src/com/example/android/systemupdatersample/util/FileDownloader.java
new file mode 100644
index 0000000..806f173
--- /dev/null
+++ b/updater_sample/src/com/example/android/systemupdatersample/util/FileDownloader.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed 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.
+ */
+
+package com.example.android.systemupdatersample.util;
+
+import android.util.Log;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.URL;
+import java.net.URLConnection;
+
+/**
+ * Downloads chunk of a file from given url using {@code offset} and {@code size},
+ * and saves to a given location.
+ *
+ * In real-life application this helper class should download from HTTP Server,
+ * but in this sample app it will only download from a local file.
+ */
+public final class FileDownloader {
+
+    private String mUrl;
+    private long mOffset;
+    private long mSize;
+    private File mOut;
+
+    public FileDownloader(String url, long offset, long size, File out)  {
+        this.mUrl = url;
+        this.mOffset = offset;
+        this.mSize = size;
+        this.mOut = out;
+    }
+
+    /**
+     * Downloads the file with given offset and size.
+     */
+    public void download() throws IOException {
+        Log.d("FileDownloader", "downloading " + mOut.getName()
+                + " from " + mUrl
+                + " to " + mOut.getAbsolutePath());
+
+        URL url = new URL(mUrl);
+        URLConnection connection = url.openConnection();
+        connection.connect();
+
+        // download the file
+        try (InputStream input = connection.getInputStream()) {
+            try (OutputStream output = new FileOutputStream(mOut)) {
+                long skipped = input.skip(mOffset);
+                if (skipped != mOffset) {
+                    throw new IOException("Can't download file "
+                            + mUrl
+                            + " with given offset "
+                            + mOffset);
+                }
+                byte[] data = new byte[4096];
+                long total = 0;
+                while (total < mSize) {
+                    int needToRead = (int) Math.min(4096, mSize - total);
+                    int count = input.read(data, 0, needToRead);
+                    if (count <= 0) {
+                        break;
+                    }
+                    output.write(data, 0, count);
+                    total += count;
+                }
+                if (total != mSize) {
+                    throw new IOException("Can't download file "
+                            + mUrl
+                            + " with given size "
+                            + mSize);
+                }
+            }
+        }
+    }
+
+}
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/UpdateConfigs.java b/updater_sample/src/com/example/android/systemupdatersample/util/UpdateConfigs.java
index 089f8b2..71d4df8 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/util/UpdateConfigs.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/util/UpdateConfigs.java
@@ -17,6 +17,7 @@
 package com.example.android.systemupdatersample.util;
 
 import android.content.Context;
+import android.util.Log;
 
 import com.example.android.systemupdatersample.UpdateConfig;
 
@@ -70,6 +71,7 @@
                             StandardCharsets.UTF_8);
                     configs.add(UpdateConfig.fromJson(json));
                 } catch (Exception e) {
+                    Log.e("UpdateConfigs", "Can't read/parse config file " + f.getName(), e);
                     throw new RuntimeException(
                             "Can't read/parse config file " + f.getName(), e);
                 }
diff --git a/updater_sample/tests/Android.mk b/updater_sample/tests/Android.mk
index 83082cd..a1a4664 100644
--- a/updater_sample/tests/Android.mk
+++ b/updater_sample/tests/Android.mk
@@ -22,11 +22,15 @@
 LOCAL_MODULE_TAGS := tests
 LOCAL_JAVA_LIBRARIES := \
     android.test.base.stubs \
-    android.test.runner.stubs
+    android.test.runner.stubs \
+    guava \
+    mockito-target-minus-junit4
 LOCAL_STATIC_JAVA_LIBRARIES := android-support-test
 LOCAL_INSTRUMENTATION_FOR := SystemUpdaterSample
 LOCAL_PROGUARD_ENABLED := disabled
 
-LOCAL_SRC_FILES := $(call all-subdir-java-files)
+LOCAL_RESOURCE_DIR := $(LOCAL_PATH)/res
+
+LOCAL_SRC_FILES := $(call all-java-files-under, src)
 
 include $(BUILD_PACKAGE)
diff --git a/updater_sample/tests/AndroidManifest.xml b/updater_sample/tests/AndroidManifest.xml
index 2392bb3..76af5f1 100644
--- a/updater_sample/tests/AndroidManifest.xml
+++ b/updater_sample/tests/AndroidManifest.xml
@@ -17,6 +17,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
       package="com.example.android.systemupdatersample.tests">
 
+    <uses-sdk android:minSdkVersion="27" android:targetSdkVersion="27" />
+
     <!-- We add an application tag here just so that we can indicate that
          this package needs to link against the android.test library,
          which is needed when building test cases. -->
diff --git a/updater_sample/tests/res/raw/update_config_stream_001.json b/updater_sample/tests/res/raw/update_config_stream_001.json
index 965f737..a9afd33 100644
--- a/updater_sample/tests/res/raw/update_config_stream_001.json
+++ b/updater_sample/tests/res/raw/update_config_stream_001.json
@@ -1,8 +1,8 @@
 {
     "name": "streaming-001",
     "url": "http://foo.bar/update.zip",
-    "type": "STREAMING",
-    "streaming_metadata": {
+    "ab_install_type": "STREAMING",
+    "ab_streaming_metadata": {
         "property_files": [
             {
                 "filename": "payload.bin",
diff --git a/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateConfigTest.java b/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateConfigTest.java
index 8715371..0975e76 100644
--- a/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateConfigTest.java
+++ b/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateConfigTest.java
@@ -19,14 +19,23 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertSame;
 
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
 
+import com.example.android.systemupdatersample.tests.R;
+import com.google.common.io.CharStreams;
+
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 import org.junit.runner.RunWith;
 
+import java.io.IOException;
+import java.io.InputStreamReader;
+
 /**
  * Tests for {@link UpdateConfig}
  */
@@ -36,27 +45,48 @@
 
     private static final String JSON_NON_STREAMING =
             "{\"name\": \"vip update\", \"url\": \"file:///builds/a.zip\", "
-            + " \"type\": \"NON_STREAMING\"}";
-
-    private static final String JSON_STREAMING =
-            "{\"name\": \"vip update 2\", \"url\": \"http://foo.bar/a.zip\", "
-            + "\"type\": \"STREAMING\"}";
+            + " \"ab_install_type\": \"NON_STREAMING\"}";
 
     @Rule
     public final ExpectedException thrown = ExpectedException.none();
 
+    private Context mContext;
+    private Context mTargetContext;
+    private String mJsonStreaming001;
+
+    @Before
+    public void setUp() throws Exception {
+        mContext = InstrumentationRegistry.getContext();
+        mTargetContext = InstrumentationRegistry.getTargetContext();
+        mJsonStreaming001 = readResource(R.raw.update_config_stream_001);
+    }
+
     @Test
-    public void fromJson_parsesJsonConfigWithoutMetadata() throws Exception {
+    public void fromJson_parsesNonStreaming() throws Exception {
         UpdateConfig config = UpdateConfig.fromJson(JSON_NON_STREAMING);
         assertEquals("name is parsed", "vip update", config.getName());
         assertEquals("stores raw json", JSON_NON_STREAMING, config.getRawJson());
-        assertSame("type is parsed", UpdateConfig.TYPE_NON_STREAMING, config.getInstallType());
+        assertSame("type is parsed",
+                UpdateConfig.AB_INSTALL_TYPE_NON_STREAMING,
+                config.getInstallType());
         assertEquals("url is parsed", "file:///builds/a.zip", config.getUrl());
     }
 
     @Test
+    public void fromJson_parsesStreaming() throws Exception {
+        UpdateConfig config = UpdateConfig.fromJson(mJsonStreaming001);
+        assertEquals("streaming-001", config.getName());
+        assertEquals("http://foo.bar/update.zip", config.getUrl());
+        assertSame(UpdateConfig.AB_INSTALL_TYPE_STREAMING, config.getInstallType());
+        assertEquals("payload.bin",
+                config.getStreamingMetadata().getPropertyFiles()[0].getFilename());
+        assertEquals(195, config.getStreamingMetadata().getPropertyFiles()[0].getOffset());
+        assertEquals(8, config.getStreamingMetadata().getPropertyFiles()[0].getSize());
+    }
+
+    @Test
     public void getUpdatePackageFile_throwsErrorIfStreaming() throws Exception {
-        UpdateConfig config = UpdateConfig.fromJson(JSON_STREAMING);
+        UpdateConfig config = UpdateConfig.fromJson(mJsonStreaming001);
         thrown.expect(RuntimeException.class);
         config.getUpdatePackageFile();
     }
@@ -64,7 +94,7 @@
     @Test
     public void getUpdatePackageFile_throwsErrorIfNotAFile() throws Exception {
         String json = "{\"name\": \"upd\", \"url\": \"http://foo.bar\","
-                + " \"type\": \"NON_STREAMING\"}";
+                + " \"ab_install_type\": \"NON_STREAMING\"}";
         UpdateConfig config = UpdateConfig.fromJson(json);
         thrown.expect(RuntimeException.class);
         config.getUpdatePackageFile();
@@ -73,7 +103,11 @@
     @Test
     public void getUpdatePackageFile_works() throws Exception {
         UpdateConfig c = UpdateConfig.fromJson(JSON_NON_STREAMING);
-        assertEquals("correct path", "/builds/a.zip", c.getUpdatePackageFile().getAbsolutePath());
+        assertEquals("/builds/a.zip", c.getUpdatePackageFile().getAbsolutePath());
     }
 
+    private String readResource(int id) throws IOException {
+        return CharStreams.toString(new InputStreamReader(
+            mContext.getResources().openRawResource(id)));
+    }
 }
diff --git a/updater_sample/tests/src/com/example/android/systemupdatersample/util/FileDownloaderTest.java b/updater_sample/tests/src/com/example/android/systemupdatersample/util/FileDownloaderTest.java
new file mode 100644
index 0000000..df47c8c
--- /dev/null
+++ b/updater_sample/tests/src/com/example/android/systemupdatersample/util/FileDownloaderTest.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed 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.
+ */
+
+package com.example.android.systemupdatersample.util;
+
+import static junit.framework.Assert.assertEquals;
+
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import com.example.android.systemupdatersample.tests.R;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+/**
+ * Tests for {@link FileDownloader}
+ */
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class FileDownloaderTest {
+
+    @Rule
+    public final ExpectedException thrown = ExpectedException.none();
+
+    private Context mTestContext;
+    private Context mTargetContext;
+
+    @Before
+    public void setUp() {
+        mTestContext = InstrumentationRegistry.getContext();
+        mTargetContext = InstrumentationRegistry.getTargetContext();
+    }
+
+    @Test
+    public void download_downloadsChunkOfZip() throws Exception {
+        // Prepare the target file
+        File packageFile = Paths
+                .get(mTargetContext.getCacheDir().getAbsolutePath(), "ota.zip")
+                .toFile();
+        Files.delete(packageFile.toPath());
+        Files.copy(mTestContext.getResources().openRawResource(R.raw.ota_002_package),
+                packageFile.toPath());
+        String url = "file://" + packageFile.getAbsolutePath();
+        // prepare where to download
+        File outFile = Paths
+                .get(mTargetContext.getCacheDir().getAbsolutePath(), "care_map.txt")
+                .toFile();
+        Files.delete(outFile.toPath());
+        // download a chunk of ota.zip
+        FileDownloader downloader = new FileDownloader(url, 160, 8, outFile);
+        downloader.download();
+        String downloadedContent = String.join("\n", Files.readAllLines(outFile.toPath()));
+        // Look at tools/create_test_ota.py
+        assertEquals("CARE_MAP", downloadedContent);
+    }
+
+}
diff --git a/updater_sample/tests/src/com/example/android/systemupdatersample/util/UpdateConfigsTest.java b/updater_sample/tests/src/com/example/android/systemupdatersample/util/UpdateConfigsTest.java
index 4aa8c64..c85698c 100644
--- a/updater_sample/tests/src/com/example/android/systemupdatersample/util/UpdateConfigsTest.java
+++ b/updater_sample/tests/src/com/example/android/systemupdatersample/util/UpdateConfigsTest.java
@@ -54,8 +54,8 @@
     @Test
     public void configsToNames_extractsNames() {
         List<UpdateConfig> configs = Arrays.asList(
-                new UpdateConfig("blah", "http://", UpdateConfig.TYPE_NON_STREAMING),
-                new UpdateConfig("blah 2", "http://", UpdateConfig.TYPE_STREAMING)
+                new UpdateConfig("blah", "http://", UpdateConfig.AB_INSTALL_TYPE_NON_STREAMING),
+                new UpdateConfig("blah 2", "http://", UpdateConfig.AB_INSTALL_TYPE_STREAMING)
         );
         String[] names = UpdateConfigs.configsToNames(configs);
         assertArrayEquals(new String[] {"blah", "blah 2"}, names);