diff --git a/app/src/androidTest/java/org/fdroid/fdroid/FileCompatTest.java b/app/src/androidTest/java/org/fdroid/fdroid/FileCompatTest.java
index 97fe44ecf..819d8539b 100644
--- a/app/src/androidTest/java/org/fdroid/fdroid/FileCompatTest.java
+++ b/app/src/androidTest/java/org/fdroid/fdroid/FileCompatTest.java
@@ -30,14 +30,13 @@ public class FileCompatTest {
 
     private static final String TAG = "FileCompatTest";
 
-    private File dir;
     private SanitizedFile sourceFile;
     private SanitizedFile destFile;
 
     @Before
     public void setUp() {
         Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
-        dir = TestUtils.getWriteableDir(instrumentation);
+        File dir = TestUtils.getWriteableDir(instrumentation);
         sourceFile = SanitizedFile.knownSanitized(TestUtils.copyAssetToDir(instrumentation.getContext(), "simpleIndex.jar", dir));
         destFile = new SanitizedFile(dir, "dest-" + UUID.randomUUID() + ".testproduct");
         assertFalse(destFile.exists());
diff --git a/app/src/main/java/org/fdroid/fdroid/localrepo/type/BluetoothSwap.java b/app/src/main/java/org/fdroid/fdroid/localrepo/type/BluetoothSwap.java
index 31c191a52..8b09c4c6f 100644
--- a/app/src/main/java/org/fdroid/fdroid/localrepo/type/BluetoothSwap.java
+++ b/app/src/main/java/org/fdroid/fdroid/localrepo/type/BluetoothSwap.java
@@ -22,7 +22,6 @@ public final class BluetoothSwap extends SwapType {
 
     @NonNull
     private final BluetoothAdapter adapter;
-    private BroadcastReceiver receiver;
     private boolean isDiscoverable;
 
     @Nullable
@@ -64,7 +63,7 @@ public final class BluetoothSwap extends SwapType {
             return;
         }
 
-        receiver = new BroadcastReceiver() {
+        BroadcastReceiver receiver = new BroadcastReceiver() {
             @Override
             public void onReceive(Context context, Intent intent) {
                 switch (intent.getIntExtra(BluetoothAdapter.EXTRA_SCAN_MODE, -1)) {
diff --git a/config/pmd/rules.xml b/config/pmd/rules.xml
index 7af77cb40..34775e15e 100644
--- a/config/pmd/rules.xml
+++ b/config/pmd/rules.xml
@@ -26,4 +26,5 @@
     <rule ref="rulesets/java/design.xml/EqualsNull"/>
     <rule ref="rulesets/java/design.xml/IdempotentOperations"/>
     <rule ref="rulesets/java/design.xml/ImmutableField"/>
+    <rule ref="rulesets/java/design.xml/SingularField"/>
 </ruleset>