diff --git a/core/java/android/os/BinderProxy.java b/core/java/android/os/BinderProxy.java
index 1929a4d562d43a90c7463168fe412315b1b6b8f0..5196b1702cc0f84433bf7cc7fae4d468447c4adb 100644
--- a/core/java/android/os/BinderProxy.java
+++ b/core/java/android/os/BinderProxy.java
@@ -32,7 +32,9 @@ import java.io.FileDescriptor;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Arrays;
+import java.util.Collections;
import java.util.HashMap;
+import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
@@ -613,15 +615,35 @@ public final class BinderProxy implements IBinder {
*/
public native boolean transactNative(int code, Parcel data, Parcel reply,
int flags) throws RemoteException;
+
+ /* This list is to hold strong reference to the death recipients that are waiting for the death
+ * of binder that this proxy references. Previously, the death recipients were strongy
+ * referenced from JNI, but that can cause memory leak (b/298374304) when the application has a
+ * strong reference from the death recipient to the proxy object. The JNI reference is now weak.
+ * And this strong reference is to keep death recipients at least until the proxy is GC'ed. */
+ private List<DeathRecipient> mDeathRecipients = Collections.synchronizedList(new ArrayList<>());
+
/**
* See {@link IBinder#linkToDeath(DeathRecipient, int)}
*/
- public native void linkToDeath(DeathRecipient recipient, int flags)
- throws RemoteException;
+ public void linkToDeath(DeathRecipient recipient, int flags)
+ throws RemoteException {
+ linkToDeathNative(recipient, flags);
+ mDeathRecipients.add(recipient);
+ }
+
/**
* See {@link IBinder#unlinkToDeath}
*/
- public native boolean unlinkToDeath(DeathRecipient recipient, int flags);
+ public boolean unlinkToDeath(DeathRecipient recipient, int flags) {
+ mDeathRecipients.remove(recipient);
+ return unlinkToDeathNative(recipient, flags);
+ }
+
+ private native void linkToDeathNative(DeathRecipient recipient, int flags)
+ throws RemoteException;
+
+ private native boolean unlinkToDeathNative(DeathRecipient recipient, int flags);
/**
* Perform a dump on the remote object
diff --git a/core/jni/android_util_Binder.cpp b/core/jni/android_util_Binder.cpp
index 6ed0a8a047f5d744036ad792dcb7981de587bdcb..f4bc2675e30df24f82d80f23baac82cd2127997b 100644
--- a/core/jni/android_util_Binder.cpp
+++ b/core/jni/android_util_Binder.cpp
@@ -17,19 +17,8 @@
#define LOG_TAG "JavaBinder"
//#define LOG_NDEBUG 0
-#include "android_os_Parcel.h"
#include "android_util_Binder.h"
-#include <atomic>
-#include <fcntl.h>
-#include <inttypes.h>
-#include <mutex>
-#include <stdio.h>
-#include <string>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
#include <android-base/stringprintf.h>
#include <binder/BpBinder.h>
#include <binder/IInterface.h>
@@ -40,7 +29,16 @@
#include <binder/Stability.h>
#include <binderthreadstate/CallerUtils.h>
#include <cutils/atomic.h>
+#include <fcntl.h>
+#include <inttypes.h>
#include <log/log.h>
+#include <nativehelper/JNIHelp.h>
+#include <nativehelper/ScopedLocalRef.h>
+#include <nativehelper/ScopedUtfChars.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
#include <utils/KeyedVector.h>
#include <utils/List.h>
#include <utils/Log.h>
@@ -48,10 +46,11 @@
#include <utils/SystemClock.h>
#include <utils/threads.h>
-#include <nativehelper/JNIHelp.h>
-#include <nativehelper/ScopedLocalRef.h>
-#include <nativehelper/ScopedUtfChars.h>
+#include <atomic>
+#include <mutex>
+#include <string>
+#include "android_os_Parcel.h"
#include "core_jni_helpers.h"
//#undef ALOGV
@@ -557,14 +556,43 @@ public:
};
// ----------------------------------------------------------------------------
+#if __BIONIC__
+#include <android/api-level.h>
+static bool target_sdk_is_at_least_vic() {
+ return android_get_application_target_sdk_version() >= __ANDROID_API_V__;
+}
+#else
+static constexpr bool target_sdk_is_at_least_vic() {
+ // If not built for Android (i.e. glibc host), follow the latest behavior as there's no compat
+ // requirement there.
+ return true;
+}
+#endif // __BIONIC__
class JavaDeathRecipient : public IBinder::DeathRecipient
{
public:
JavaDeathRecipient(JNIEnv* env, jobject object, const sp<DeathRecipientList>& list)
- : mVM(jnienv_to_javavm(env)), mObject(env->NewGlobalRef(object)),
- mObjectWeak(NULL), mList(list)
- {
+ : mVM(jnienv_to_javavm(env)), mObject(NULL), mObjectWeak(NULL), mList(list) {
+ // b/298374304: For apps targeting Android V or beyond, we no longer hold the global JNI ref
+ // to the death recipient objects. This is to prevent the memory leak which can happen when
+ // the death recipient object internally has a strong reference to the proxy object. Under
+ // the old behavior, you were unable to kill the binder service by dropping all references
+ // to the proxy object - because it is still strong referenced from JNI (here). The only way
+ // to cut the strong reference was to call unlinkDeath(), but it was easy to forget.
+ //
+ // Now, the strong reference to the death recipient is held in the Java-side proxy object.
+ // See BinderProxy.mDeathRecipients. From JNI, only the weak reference is kept. An
+ // implication of this is that you may not receive binderDied() if you drop all references
+ // to the proxy object before the service dies. This should be okay for most cases because
+ // you normally are not interested in the death of a binder service which you don't have any
+ // reference to. If however you want to get binderDied() regardless of the proxy object's
+ // lifecycle, keep a strong reference to the death recipient object by yourself.
+ if (target_sdk_is_at_least_vic()) {
+ mObjectWeak = env->NewWeakGlobalRef(object);
+ } else {
+ mObject = env->NewGlobalRef(object);
+ }
// These objects manage their own lifetimes so are responsible for final bookkeeping.
// The list holds a strong reference to this object.
LOGDEATH("Adding JDR %p to DRL %p", this, list.get());
@@ -577,26 +605,49 @@ public:
void binderDied(const wp<IBinder>& who)
{
LOGDEATH("Receiving binderDied() on JavaDeathRecipient %p\n", this);
- if (mObject != NULL) {
- JNIEnv* env = javavm_to_jnienv(mVM);
- ScopedLocalRef<jobject> jBinderProxy(env, javaObjectForIBinder(env, who.promote()));
- env->CallStaticVoidMethod(gBinderProxyOffsets.mClass,
- gBinderProxyOffsets.mSendDeathNotice, mObject,
- jBinderProxy.get());
- if (env->ExceptionCheck()) {
- jthrowable excep = env->ExceptionOccurred();
- binder_report_exception(env, excep,
- "*** Uncaught exception returned from death notification!");
- }
+ if (mObject == NULL && mObjectWeak == NULL) {
+ return;
+ }
+ JNIEnv* env = javavm_to_jnienv(mVM);
+ ScopedLocalRef<jobject> jBinderProxy(env, javaObjectForIBinder(env, who.promote()));
+
+ // Hold a local reference to the recipient. This may fail if the recipient is weakly
+ // referenced, in which case we can't deliver the death notice.
+ ScopedLocalRef<jobject> jRecipient(env,
+ env->NewLocalRef(mObject != NULL ? mObject
+ : mObjectWeak));
+ if (jRecipient.get() == NULL) {
+ ALOGW("Binder died, but death recipient is already garbage collected. If your target "
+ "sdk level is at or above 35, this can happen when you dropped all references to "
+ "the binder service before it died. If you want to get a death notice for a "
+ "binder service which you have no reference to, keep a strong reference to the "
+ "death recipient by yourself.");
+ return;
+ }
- // Serialize with our containing DeathRecipientList so that we can't
- // delete the global ref on mObject while the list is being iterated.
+ if (mFired) {
+ ALOGW("Received multiple death notices for the same binder object. Binder driver bug?");
+ return;
+ }
+ mFired = true;
+
+ env->CallStaticVoidMethod(gBinderProxyOffsets.mClass, gBinderProxyOffsets.mSendDeathNotice,
+ jRecipient.get(), jBinderProxy.get());
+ if (env->ExceptionCheck()) {
+ jthrowable excep = env->ExceptionOccurred();
+ binder_report_exception(env, excep,
+ "*** Uncaught exception returned from death notification!");
+ }
+
+ // Demote from strong ref (if exists) to weak after binderDied() has been delivered, to
+ // allow the DeathRecipient and BinderProxy to be GC'd if no longer needed. Do this in sync
+ // with our containing DeathRecipientList so that we can't delete the global ref on mObject
+ // while the list is being iterated.
+ if (mObject != NULL) {
sp<DeathRecipientList> list = mList.promote();
if (list != NULL) {
AutoMutex _l(list->lock());
- // Demote from strong ref to weak after binderDied() has been delivered,
- // to allow the DeathRecipient and BinderProxy to be GC'd if no longer needed.
mObjectWeak = env->NewWeakGlobalRef(mObject);
env->DeleteGlobalRef(mObject);
mObject = NULL;
@@ -663,9 +714,19 @@ protected:
private:
JavaVM* const mVM;
- jobject mObject; // Initial strong ref to Java-side DeathRecipient. Cleared on binderDied().
- jweak mObjectWeak; // Weak ref to the same Java-side DeathRecipient after binderDied().
+
+ // If target sdk version < 35, the Java-side DeathRecipient is strongly referenced from mObject
+ // upon linkToDeath() and then after binderDied() is called, the strong reference is demoted to
+ // a weak reference (mObjectWeak).
+ // If target sdk version >= 35, the strong reference is never made here (i.e. mObject == NULL
+ // always). Instead, the strong reference to the Java-side DeathRecipient is made in
+ // BinderProxy.mDeathRecipients. In the native world, only the weak reference is kept.
+ jobject mObject;
+ jweak mObjectWeak;
wp<DeathRecipientList> mList;
+
+ // Whether binderDied was called or not.
+ bool mFired = false;
};
// ----------------------------------------------------------------------------
@@ -1452,17 +1513,19 @@ static jobject android_os_BinderProxy_getExtension(JNIEnv* env, jobject obj) {
// ----------------------------------------------------------------------------
+// clang-format off
static const JNINativeMethod gBinderProxyMethods[] = {
/* name, signature, funcPtr */
{"pingBinder", "()Z", (void*)android_os_BinderProxy_pingBinder},
{"isBinderAlive", "()Z", (void*)android_os_BinderProxy_isBinderAlive},
{"getInterfaceDescriptor", "()Ljava/lang/String;", (void*)android_os_BinderProxy_getInterfaceDescriptor},
{"transactNative", "(ILandroid/os/Parcel;Landroid/os/Parcel;I)Z", (void*)android_os_BinderProxy_transact},
- {"linkToDeath", "(Landroid/os/IBinder$DeathRecipient;I)V", (void*)android_os_BinderProxy_linkToDeath},
- {"unlinkToDeath", "(Landroid/os/IBinder$DeathRecipient;I)Z", (void*)android_os_BinderProxy_unlinkToDeath},
+ {"linkToDeathNative", "(Landroid/os/IBinder$DeathRecipient;I)V", (void*)android_os_BinderProxy_linkToDeath},
+ {"unlinkToDeathNative", "(Landroid/os/IBinder$DeathRecipient;I)Z", (void*)android_os_BinderProxy_unlinkToDeath},
{"getNativeFinalizer", "()J", (void*)android_os_BinderProxy_getNativeFinalizer},
{"getExtension", "()Landroid/os/IBinder;", (void*)android_os_BinderProxy_getExtension},
};
+// clang-format on
const char* const kBinderProxyPathName = "android/os/BinderProxy";
diff --git a/tests/BinderLeakTest/Android.bp b/tests/BinderLeakTest/Android.bp
new file mode 100644
index 0000000000000000000000000000000000000000..78b0ede76d4e01b15aff2bd67d8d02e01b32adae
--- /dev/null
+++ b/tests/BinderLeakTest/Android.bp
@@ -0,0 +1,40 @@
+package {
+ // See: http://go/android-license-faq
+ // A large-scale-change added 'default_applicable_licenses' to import
+ // all of the 'license_kinds' from "frameworks_base_license"
+ // to get the below license kinds:
+ // SPDX-license-identifier-Apache-2.0
+ default_applicable_licenses: ["frameworks_base_license"],
+}
+
+filegroup {
+ name: "binder_leak_test_aidl",
+ srcs: ["**/*.aidl"],
+ path: "aidl",
+}
+
+java_defaults {
+ name: "BinderTest.defaults",
+ srcs: [
+ "**/*.java",
+ ":binder_leak_test_aidl",
+ ],
+ static_libs: [
+ "androidx.test.ext.junit",
+ "androidx.test.rules",
+ "androidx.test.runner",
+ ],
+}
+
+// Built with target_sdk_version: current
+android_test {
+ name: "BinderLeakTest",
+ defaults: ["BinderTest.defaults"],
+}
+
+// Built with target_sdk_version: 33
+android_test {
+ name: "BinderLeakTest_legacy",
+ defaults: ["BinderTest.defaults"],
+ manifest: "AndroidManifest_legacy.xml",
+}
diff --git a/tests/BinderLeakTest/AndroidManifest.xml b/tests/BinderLeakTest/AndroidManifest.xml
new file mode 100644
index 0000000000000000000000000000000000000000..756def7ac29de3f7570b9fbd26504c62b69514d5
--- /dev/null
+++ b/tests/BinderLeakTest/AndroidManifest.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+ package="com.android.test.binder">
+ <application>
+ <service
+ android:name=".MyService"
+ android:enabled="true"
+ android:exported="true"
+ android:process=":service">
+ </service>
+ </application>
+
+ <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+ android:targetPackage="com.android.test.binder"
+ android:label="Binder leak test">
+ </instrumentation>
+</manifest>
diff --git a/tests/BinderLeakTest/AndroidManifest_legacy.xml b/tests/BinderLeakTest/AndroidManifest_legacy.xml
new file mode 100644
index 0000000000000000000000000000000000000000..03d1dfd1fd8389493036d97cd8df009458d86f39
--- /dev/null
+++ b/tests/BinderLeakTest/AndroidManifest_legacy.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+ package="com.android.test.binder">
+ <uses-sdk android:minSdkVersion="33"
+ android:targetSdkVersion="33"
+ android:maxSdkVersion="33" />
+ <application>
+ <service
+ android:name=".MyService"
+ android:enabled="true"
+ android:exported="true"
+ android:process=":service">
+ </service>
+ </application>
+
+ <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+ android:targetPackage="com.android.test.binder"
+ android:label="Binder leak test">
+ </instrumentation>
+</manifest>
diff --git a/tests/BinderLeakTest/aidl/com/android/test/binder/IFoo.aidl b/tests/BinderLeakTest/aidl/com/android/test/binder/IFoo.aidl
new file mode 100644
index 0000000000000000000000000000000000000000..a721959d19b4b20448d8f053e9571ce95cbb4cc3
--- /dev/null
+++ b/tests/BinderLeakTest/aidl/com/android/test/binder/IFoo.aidl
@@ -0,0 +1,5 @@
+package com.android.test.binder;
+
+interface IFoo {
+
+}
diff --git a/tests/BinderLeakTest/aidl/com/android/test/binder/IFooProvider.aidl b/tests/BinderLeakTest/aidl/com/android/test/binder/IFooProvider.aidl
new file mode 100644
index 0000000000000000000000000000000000000000..b487f51f812cabf852eaad85c43bda85a0ef0733
--- /dev/null
+++ b/tests/BinderLeakTest/aidl/com/android/test/binder/IFooProvider.aidl
@@ -0,0 +1,10 @@
+package com.android.test.binder;
+import com.android.test.binder.IFoo;
+
+interface IFooProvider {
+ IFoo createFoo();
+
+ boolean isFooGarbageCollected();
+
+ oneway void killProcess();
+}
diff --git a/tests/BinderLeakTest/java/com/android/test/binder/BinderTest.java b/tests/BinderLeakTest/java/com/android/test/binder/BinderTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..f07317f7d5f3621d4927281a1ac9ee737e65c824
--- /dev/null
+++ b/tests/BinderLeakTest/java/com/android/test/binder/BinderTest.java
@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2023 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.android.test.binder;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+import android.content.Intent;
+import android.os.Build;
+import android.os.IBinder;
+import android.os.RemoteException;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.rule.ServiceTestRule;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.lang.ref.PhantomReference;
+import java.lang.ref.ReferenceQueue;
+import java.util.concurrent.TimeoutException;
+
+@RunWith(AndroidJUnit4.class)
+public class BinderTest {
+ @Rule
+ public final ServiceTestRule serviceRule = new ServiceTestRule();
+
+ @Test
+ public void testDeathRecipientLeaksOrNot()
+ throws RemoteException, TimeoutException, InterruptedException {
+ Intent intent = new Intent(ApplicationProvider.getApplicationContext(), MyService.class);
+ IFooProvider provider = IFooProvider.Stub.asInterface(serviceRule.bindService(intent));
+ FooHolder holder = new FooHolder(provider.createFoo());
+
+ // ref will get enqueued right after holder is finalized for gc.
+ ReferenceQueue<FooHolder> refQueue = new ReferenceQueue<>();
+ PhantomReference<FooHolder> ref = new PhantomReference<>(holder, refQueue);
+
+ DeathRecorder deathRecorder = new DeathRecorder();
+ holder.registerDeathRecorder(deathRecorder);
+
+ if (getSdkVersion() >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
+ /////////////////////////////////////////////
+ // New behavior
+ //
+ // Reference chain at this moment:
+ // holder --(java strong ref)--> FooHolder
+ // FooHolder.mProxy --(java strong ref)--> IFoo.Proxy
+ // IFoo.Proxy.mRemote --(java strong ref)--> BinderProxy
+ // BinderProxy --(binder ref)--> Foo.Stub
+ // In other words, the variable "holder" is the root of the reference chain.
+
+ // By setting the variable to null, we make FooHolder, IFoo.Proxy, BinderProxy, and even
+ // Foo.Stub unreachable.
+ holder = null;
+
+ // Ensure that the objects are garbage collected
+ forceGc();
+ assertEquals(ref, refQueue.poll());
+ assertTrue(provider.isFooGarbageCollected());
+
+ // The binder has died, but we don't get notified since the death recipient is GC'ed.
+ provider.killProcess();
+ Thread.sleep(1000); // give some time for the service process to die and reaped
+ assertFalse(deathRecorder.deathRecorded);
+ } else {
+ /////////////////////////////////////////////
+ // Legacy behavior
+ //
+ // Reference chain at this moment:
+ // JavaDeathRecipient --(JNI strong ref)--> FooHolder
+ // holder --(java strong ref)--> FooHolder
+ // FooHolder.mProxy --(java strong ref)--> IFoo.Proxy
+ // IFoo.Proxy.mRemote --(java strong ref)--> BinderProxy
+ // BinderProxy --(binder ref)--> Foo.Stub
+ // So, BOTH JavaDeathRecipient and holder are roots of the reference chain.
+
+ // Even if we set holder to null, it doesn't make other objects unreachable; they are
+ // still reachable via the JNI strong ref.
+ holder = null;
+
+ // Check that objects are not garbage collected
+ forceGc();
+ assertNotEquals(ref, refQueue.poll());
+ assertFalse(provider.isFooGarbageCollected());
+
+ // The legacy behavior is getting notified even when there's no reference
+ provider.killProcess();
+ Thread.sleep(1000); // give some time for the service process to die and reaped
+ assertTrue(deathRecorder.deathRecorded);
+ }
+ }
+
+ static class FooHolder implements IBinder.DeathRecipient {
+ private IFoo mProxy;
+ private DeathRecorder mDeathRecorder;
+
+ FooHolder(IFoo proxy) throws RemoteException {
+ proxy.asBinder().linkToDeath(this, 0);
+
+ // A strong reference from DeathRecipient(this) to the binder proxy is created here
+ mProxy = proxy;
+ }
+
+ public void registerDeathRecorder(DeathRecorder dr) {
+ mDeathRecorder = dr;
+ }
+
+ @Override
+ public void binderDied() {
+ if (mDeathRecorder != null) {
+ mDeathRecorder.deathRecorded = true;
+ }
+ }
+ }
+
+ static class DeathRecorder {
+ public boolean deathRecorded = false;
+ }
+
+ // Try calling System.gc() until an orphaned object is confirmed to be finalized
+ private static void forceGc() {
+ Object obj = new Object();
+ ReferenceQueue<Object> refQueue = new ReferenceQueue<>();
+ PhantomReference<Object> ref = new PhantomReference<>(obj, refQueue);
+ obj = null; // make it an orphan
+ while (refQueue.poll() != ref) {
+ System.gc();
+ }
+ }
+
+ private static int getSdkVersion() {
+ return ApplicationProvider.getApplicationContext().getApplicationInfo().targetSdkVersion;
+ }
+}
diff --git a/tests/BinderLeakTest/java/com/android/test/binder/MyService.java b/tests/BinderLeakTest/java/com/android/test/binder/MyService.java
new file mode 100644
index 0000000000000000000000000000000000000000..c701253446f4a1e2a0849d32f5632097340813a2
--- /dev/null
+++ b/tests/BinderLeakTest/java/com/android/test/binder/MyService.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2023 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.android.test.binder;
+
+import android.app.Service;
+import android.content.Intent;
+import android.os.IBinder;
+import android.os.RemoteException;
+
+import java.lang.ref.PhantomReference;
+import java.lang.ref.ReferenceQueue;
+
+public class MyService extends Service {
+ @Override
+ public IBinder onBind(Intent intent) {
+ return new IFooProvider.Stub() {
+ ReferenceQueue<IFoo> mRefQueue = new ReferenceQueue<>();
+ PhantomReference<IFoo> mRef;
+
+ @Override
+ public IFoo createFoo() throws RemoteException {
+ IFoo binder = new IFoo.Stub() {};
+ mRef = new PhantomReference<>(binder, mRefQueue);
+ return binder;
+ }
+
+ @Override
+ public boolean isFooGarbageCollected() throws RemoteException {
+ forceGc();
+ return mRefQueue.poll() == mRef;
+ }
+
+ @Override
+ public void killProcess() throws RemoteException {
+ android.os.Process.killProcess(android.os.Process.myPid());
+ }
+ };
+ }
+
+ private static void forceGc() {
+ Object obj = new Object();
+ ReferenceQueue<Object> refQueue = new ReferenceQueue<>();
+ PhantomReference<Object> ref = new PhantomReference<>(obj, refQueue);
+ obj = null; // make it an orphan
+ while (refQueue.poll() != ref) {
+ System.gc();
+ }
+ }
+}