diff --git a/javalib/src/android/system/virtualmachine/VirtualMachine.java b/javalib/src/android/system/virtualmachine/VirtualMachine.java
index d1742b2..d73bc81 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachine.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachine.java
@@ -69,7 +69,6 @@
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -319,13 +318,7 @@
 
         try {
             VirtualMachine vm = new VirtualMachine(context, name, config);
-
-            try (FileOutputStream output = new FileOutputStream(vm.mConfigFilePath)) {
-                config.serialize(output);
-            } catch (IOException e) {
-                throw new VirtualMachineException("failed to write VM config", e);
-            }
-
+            config.serialize(vm.mConfigFilePath);
             try {
                 vm.mInstanceFilePath.createNewFile();
             } catch (IOException e) {
@@ -846,14 +839,7 @@
                 throw new VirtualMachineException("incompatible config");
             }
             checkStopped();
-
-            try {
-                FileOutputStream output = new FileOutputStream(mConfigFilePath);
-                newConfig.serialize(output);
-                output.close();
-            } catch (IOException e) {
-                throw new VirtualMachineException("Failed to persist config", e);
-            }
+            newConfig.serialize(mConfigFilePath);
             mConfig = newConfig;
             return oldConfig;
         }
diff --git a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
index b814367..d1a18ae 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
@@ -34,6 +34,7 @@
 
 import java.io.File;
 import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -215,8 +216,17 @@
                 protectedVm, memoryMib, numCpus);
     }
 
+    /** Persists this config to a file. */
+    void serialize(@NonNull File file) throws VirtualMachineException {
+        try (FileOutputStream output = new FileOutputStream(file)) {
+            serializeOutputStream(output);
+        } catch (IOException e) {
+            throw new VirtualMachineException("failed to write VM config", e);
+        }
+    }
+
     /** Persists this config to a stream, for example a file. */
-    void serialize(@NonNull OutputStream output) throws IOException {
+    private void serializeOutputStream(@NonNull OutputStream output) throws IOException {
         PersistableBundle b = new PersistableBundle();
         b.putInt(KEY_VERSION, VERSION);
         b.putString(KEY_APKPATH, mApkPath);