android: Cleanup classes

- Use final modifer wherever possible
- Use try-with-resources for input/output streams

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

app/src/main/java/com/wireguard/android/util/SharedLibraryLoader.java

@@ -22,7 +22,7 @@ public final class SharedLibraryLoader {
     private SharedLibraryLoader() {
     }
 
-    public static final void loadSharedLibrary(final Context context, final String libName) {
+    public static void loadSharedLibrary(final Context context, final String libName) {
         Throwable noAbiException;
         try {
             System.loadLibrary(libName);
@@ -35,12 +35,12 @@ public final class SharedLibraryLoader {
         final ZipFile zipFile;
         try {
             zipFile = new ZipFile(new File(context.getApplicationInfo().sourceDir), ZipFile.OPEN_READ);
-        } catch (IOException e) {
+        } catch (final IOException e) {
             throw new RuntimeException(e);
         }
 
         final String mappedLibName = System.mapLibraryName(libName);
-        byte buffer[] = new byte[1024 * 32];
+        final byte[] buffer = new byte[1024 * 32];
         for (final String abi : Build.SUPPORTED_ABIS) {
             final String libZipPath = "lib" + File.separatorChar + abi + File.separatorChar + mappedLibName;
             final ZipEntry zipEntry = zipFile.getEntry(libZipPath);
@@ -50,13 +50,13 @@ public final class SharedLibraryLoader {
             try {
                 f = File.createTempFile("lib", ".so", context.getCacheDir());
                 Log.d(TAG, "Extracting apk:/" + libZipPath + " to " + f.getAbsolutePath() + " and loading");
-                FileOutputStream out = new FileOutputStream(f);
-                InputStream in = zipFile.getInputStream(zipEntry);
-                int len;
-                while ((len = in.read(buffer)) != -1) {
-                    out.write(buffer, 0, len);
+                try (final FileOutputStream out = new FileOutputStream(f);
+                     final InputStream in = zipFile.getInputStream(zipEntry)) {
+                    int len;
+                    while ((len = in.read(buffer)) != -1) {
+                        out.write(buffer, 0, len);
+                    }
                 }
-                out.close();
                 System.load(f.getAbsolutePath());
                 return;
             } catch (Exception e) {
@@ -64,6 +64,7 @@ public final class SharedLibraryLoader {
                 noAbiException = e;
             } finally {
                 if (f != null)
+                    // noinspection ResultOfMethodCallIgnored
                     f.delete();
             }
         }

app/src/main/java/com/wireguard/android/util/ToolsInstaller.java

@@ -58,7 +58,7 @@ public final class ToolsInstaller {
 
     public CompletionStage<String> getVersion() {
         return Application.getComponent().getAsyncWorker().supplyAsync(() -> {
-            final ArrayList<String> output = new ArrayList<>();
+            final List<String> output = new ArrayList<>();
             if (rootShell.run(output, "cat /sys/module/wireguard/version") != 0 || output.isEmpty())
                 throw new RuntimeException("Unable to determine kernel module version");
             return output.get(0);

app/src/main/java/com/wireguard/android/util/Topic.java

@@ -28,7 +28,7 @@ public class Topic {
         subscribers = new SyncArrayList<>();
     }
 
-    public synchronized void subscribe(Subscriber sub) {
+    public synchronized void subscribe(final Subscriber sub) {
         subscribers.add(new WeakReference<>(sub));
     }
 
@@ -36,10 +36,10 @@ public class Topic {
         subscribers = new SyncArrayList<>();
     }
 
-    public synchronized void unsubscribe(Subscriber sub) {
+    public synchronized void unsubscribe(final Subscriber sub) {
         List<WeakReference<Subscriber>> subs = subscribers;
         subscribers = new ArrayList<>();
-        for (WeakReference<Subscriber> subscriber : subs) {
+        for (final WeakReference<Subscriber> subscriber : subs) {
             if (subscriber.get() != null && subscriber.get() != sub)
                 subscribers.add(subscriber);
         }
@@ -64,7 +64,7 @@ public class Topic {
         this.results = results;
         // Snapshot
         List<WeakReference<Subscriber>> subs = subscribers;
-        for (WeakReference<Subscriber> subscriber : subs) {
+        for (final WeakReference<Subscriber> subscriber : subs) {
             if (subscriber != null && subscriber.get() != null)
                 subscriber.get().onTopicPublished(this);
         }
@@ -84,7 +84,7 @@ public class Topic {
 
     public interface Subscriber {
         default void subscribeTopics() {
-            for (Topic topic : getSubscription()) {
+            for (final Topic topic : getSubscription()) {
                 if (topic.isPublished()) {
                     onTopicPublished(topic);
                 }
@@ -92,7 +92,7 @@ public class Topic {
             }
         }
         default void unsubscribeTopics() {
-            for (Topic event : getSubscription()) {
+            for (final Topic event : getSubscription()) {
                 event.unsubscribe(this);
             }
         }
@@ -102,7 +102,7 @@ public class Topic {
 
     private static class SyncArrayList<E> extends ArrayList<E> {
         @Override
-        public synchronized boolean add(E e) {
+        public synchronized boolean add(final E e) {
             return super.add(e);
         }
     }