Merge "Document that SystemProperties.set() can throw RuntimeException"

core/java/android/os/SystemProperties.java

@@ -184,6 +184,8 @@ public class SystemProperties {
      * Set the value for the given {@code key} to {@code val}.
      *
      * @throws IllegalArgumentException if the {@code val} exceeds 91 characters
+     * @throws RuntimeException if the property cannot be set, for example, if it was blocked by
+     * SELinux. libc will log the underlying reason.
      * @hide
      */
     @UnsupportedAppUsage

core/jni/android_os_SystemProperties.cpp

@@ -109,7 +109,7 @@ void SystemProperties_set(JNIEnv *env, jobject clazz, jstring keyJ,
     if (!ConvertKeyAndForward(env, keyJ, true, handler)) {
         // Must have been a failure in SetProperty.
         jniThrowException(env, "java/lang/RuntimeException",
-                          "failed to set system property");
+                          "failed to set system property (check logcat for reason)");
     }
 }