global: Clean up Java

Address Java and Android lints.

Signed-off-by: Samuel Holland <samuel@sholland.org>

8 files changed, 97 insertions, 89 deletions

diff --git a/app/src/main/java/com/wireguard/android/activity/BaseActivity.java b/app/src/main/java/com/wireguard/android/activity/BaseActivity.java
index eb2de5ed..6ee9ff14 100644
--- a/app/src/main/java/com/wireguard/android/activity/BaseActivity.java
+++ b/app/src/main/java/com/wireguard/android/activity/BaseActivity.java
@@ -49,7 +49,7 @@ public abstract class BaseActivity extends AppCompatActivity {
         super.onCreate(savedInstanceState);
 
         if (Application.getComponent().getBackendType() == GoBackend.class) {
-            Intent intent = GoBackend.VpnService.prepare(this);
+            final Intent intent = GoBackend.VpnService.prepare(this);
             if (intent != null) {
                 startActivityForResult(intent, 0);
             }
diff --git a/app/src/main/java/com/wireguard/android/activity/MainActivity.java b/app/src/main/java/com/wireguard/android/activity/MainActivity.java
index bfb3be7e..307d0bf6 100644
--- a/app/src/main/java/com/wireguard/android/activity/MainActivity.java
+++ b/app/src/main/java/com/wireguard/android/activity/MainActivity.java
@@ -68,7 +68,7 @@ public class MainActivity extends BaseActivity {
             fragment =
                     ((TunnelListFragment)
                             getSupportFragmentManager().getFragments().get(0));
-        } catch (ClassCastException ignored) {
+        } catch (final ClassCastException ignored) {
         }
         if (fragment == null || !(fragment.collapseActionMenu())) {
             if (!moveToState(State.ofLayer(state.layer - 1)))
diff --git a/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java b/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java
index fb5e7a09..46a90daa 100644
--- a/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java
+++ b/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java
@@ -17,28 +17,29 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
  * Interface for changing application-global persistent settings.
  */
 
 public class SettingsActivity extends AppCompatActivity {
-    private HashMap<Integer, PermissionRequestCallback> permissionRequestCallbacks = new HashMap<>();
-    private int permissionRequestCounter = 0;
+    private final Map<Integer, PermissionRequestCallback> permissionRequestCallbacks = new HashMap<>();
+    private int permissionRequestCounter;
 
-    public synchronized void ensurePermissions(String[] permissions, PermissionRequestCallback cb) {
-        List<String> needPermissions = new ArrayList<>(permissions.length);
+    public void ensurePermissions(final String[] permissions, final PermissionRequestCallback cb) {
+        final List<String> needPermissions = new ArrayList<>(permissions.length);
         for (final String permission : permissions) {
             if (ActivityCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED)
                 needPermissions.add(permission);
         }
         if (needPermissions.isEmpty()) {
-            int[] granted = new int[permissions.length];
+            final int[] granted = new int[permissions.length];
             Arrays.fill(granted, PackageManager.PERMISSION_GRANTED);
             cb.done(permissions, granted);
             return;
         }
-        int idx = permissionRequestCounter++;
+        final int idx = permissionRequestCounter++;
         permissionRequestCallbacks.put(idx, cb);
         ActivityCompat.requestPermissions(this, needPermissions.toArray(new String[needPermissions.size()]), idx);
     }
@@ -54,7 +55,7 @@ public class SettingsActivity extends AppCompatActivity {
     }
 
     @Override
-    public boolean onOptionsItemSelected(MenuItem item) {
+    public boolean onOptionsItemSelected(final MenuItem item) {
         switch (item.getItemId()) {
             case android.R.id.home:
                 finish();
@@ -65,7 +66,7 @@ public class SettingsActivity extends AppCompatActivity {
     }
 
     @Override
-    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
+    public void onRequestPermissionsResult(final int requestCode, @NonNull final String[] permissions, @NonNull final int[] grantResults) {
         final PermissionRequestCallback f = permissionRequestCallbacks.get(requestCode);
         if (f != null) {
             permissionRequestCallbacks.remove(requestCode);
@@ -73,7 +74,6 @@ public class SettingsActivity extends AppCompatActivity {
         }
     }
 
-    @FunctionalInterface
     public interface PermissionRequestCallback {
         void done(String[] permissions, int[] grantResults);
     }
diff --git a/app/src/main/java/com/wireguard/android/backend/GoBackend.java b/app/src/main/java/com/wireguard/android/backend/GoBackend.java
index 519f7427..e055c353 100644
--- a/app/src/main/java/com/wireguard/android/backend/GoBackend.java
+++ b/app/src/main/java/com/wireguard/android/backend/GoBackend.java
@@ -33,11 +33,11 @@ public final class GoBackend implements Backend {
         System.loadLibrary("wg-go");
     }
 
-    private Context context;
+    private final Context context;
     private Tunnel currentTunnel;
     private int currentTunnelHandle = -1;
 
-    public GoBackend(Context context) {
+    public GoBackend(final Context context) {
         this.context = context;
     }
 
@@ -108,14 +108,14 @@ public final class GoBackend implements Backend {
             if (VpnService.prepare(context) != null)
                 throw new Exception("VPN service not authorized by user");
 
-            VpnService service;
+            final VpnService service;
             if (!vpnService.isDone())
                 startVpnService();
 
             try {
                 service = vpnService.get(2, TimeUnit.SECONDS);
-            } catch (TimeoutException e) {
-                throw new Exception("Unable to start Android VPN service");
+            } catch (final TimeoutException e) {
+                throw new Exception("Unable to start Android VPN service", e);
             }
 
             if (currentTunnelHandle != -1) {
@@ -124,29 +124,32 @@ public final class GoBackend implements Backend {
             }
 
             // Build config
-            Formatter fmt = new Formatter(new StringBuilder());
             final Interface iface = config.getInterface();
-            fmt.format("replace_peers=true\n");
-            if (iface.getPrivateKey() != null)
-                fmt.format("private_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(iface.getPrivateKey())));
-            if (iface.getListenPort() != 0)
-                fmt.format("listen_port=%d\n", config.getInterface().getListenPort());
-            for (final Peer peer : config.getPeers()) {
-                if (peer.getPublicKey() != null)
-                    fmt.format("public_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(peer.getPublicKey())));
-                if (peer.getPreSharedKey() != null)
-                    fmt.format("preshared_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(peer.getPreSharedKey())));
-                if (peer.getEndpoint() != null)
-                    fmt.format("endpoint=%s\n", peer.getResolvedEndpointString());
-                if (peer.getPersistentKeepalive() != 0)
-                    fmt.format("persistent_keepalive_interval=%d\n", peer.getPersistentKeepalive());
-                for (final IPCidr addr : peer.getAllowedIPs()) {
-                    fmt.format("allowed_ip=%s\n", addr.toString());
+            final String goConfig;
+            try (Formatter fmt = new Formatter(new StringBuilder())) {
+                fmt.format("replace_peers=true\n");
+                if (iface.getPrivateKey() != null)
+                    fmt.format("private_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(iface.getPrivateKey())));
+                if (iface.getListenPort() != 0)
+                    fmt.format("listen_port=%d\n", config.getInterface().getListenPort());
+                for (final Peer peer : config.getPeers()) {
+                    if (peer.getPublicKey() != null)
+                        fmt.format("public_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(peer.getPublicKey())));
+                    if (peer.getPreSharedKey() != null)
+                        fmt.format("preshared_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(peer.getPreSharedKey())));
+                    if (peer.getEndpoint() != null)
+                        fmt.format("endpoint=%s\n", peer.getResolvedEndpointString());
+                    if (peer.getPersistentKeepalive() != 0)
+                        fmt.format("persistent_keepalive_interval=%d\n", peer.getPersistentKeepalive());
+                    for (final IPCidr addr : peer.getAllowedIPs()) {
+                        fmt.format("allowed_ip=%s\n", addr.toString());
+                    }
                 }
+                goConfig = fmt.toString();
             }
 
             // Create the vpn tunnel with android API
-            VpnService.Builder builder = service.getBuilder();
+            final VpnService.Builder builder = service.getBuilder();
             builder.setSession(tunnel.getName());
 
             for (final IPCidr addr : config.getInterface().getAddresses())
@@ -166,13 +169,13 @@ public final class GoBackend implements Backend {
             builder.setMtu(mtu);
 
             builder.setBlocking(true);
-            ParcelFileDescriptor tun = builder.establish();
+            final ParcelFileDescriptor tun = builder.establish();
             if (tun == null)
                 throw new Exception("Unable to create tun device");
 
-            currentTunnelHandle = wgTurnOn(tunnel.getName(), tun.detachFd(), fmt.toString());
+            currentTunnelHandle = wgTurnOn(tunnel.getName(), tun.detachFd(), goConfig);
             if (currentTunnelHandle < 0)
-                throw new Exception("Unable to turn tunnel on (wgTurnOn return " + currentTunnelHandle + ")");
+                throw new Exception("Unable to turn tunnel on (wgTurnOn return " + currentTunnelHandle + ')');
 
             currentTunnel = tunnel;
 
diff --git a/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java b/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
index b91d8476..b9eb3461 100644
--- a/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
+++ b/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
@@ -105,14 +105,15 @@ public final class WgQuickBackend implements Backend {
         }
         final String command = String.format("wg-quick %s '%s'", state.toString().toLowerCase(), tempFile.getAbsolutePath());
         final int result = rootShell.run(null, command);
+        // noinspection ResultOfMethodCallIgnored
         tempFile.delete();
         if (result != 0)
             throw new Exception("Unable to configure tunnel (wg-quick returned " + result + ')');
     }
 
-    public final static class WgQuickChangeReceiver extends BroadcastReceiver {
+    public static final class WgQuickChangeReceiver extends BroadcastReceiver {
         @Override
-        public void onReceive(Context context, Intent intent) {
+        public void onReceive(final Context context, final Intent intent) {
             Log.d(TAG, "Refreshing tunnel states");
             Application.getComponent().getTunnelManager().refreshTunnelStates();
         }
diff --git a/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java b/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
index a3760ed9..f0731587 100644
--- a/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
+++ b/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
@@ -109,10 +109,10 @@ public class TunnelEditorFragment extends BaseFragment {
     public boolean onOptionsItemSelected(final MenuItem item) {
         switch (item.getItemId()) {
             case R.id.menu_action_save:
-                Config newConfig = new Config();
+                final Config newConfig = new Config();
                 try {
                     binding.getConfig().commitData(newConfig);
-                } catch (Exception e) {
+                } catch (final Exception e) {
                     final String error = ExceptionLoggers.unwrap(e).getMessage();
                     final String tunnelName = tunnel == null ? binding.getConfig().getName() : tunnel.getName();
                     final String message = getString(R.string.config_save_error, tunnelName, error);
@@ -202,8 +202,8 @@ public class TunnelEditorFragment extends BaseFragment {
             onSelectedTunnelChanged(null, getSelectedTunnel());
         } else {
             tunnel = getSelectedTunnel();
-            Config.Observable config = savedInstanceState.getParcelable(KEY_LOCAL_CONFIG);
-            String originalName = savedInstanceState.getString(KEY_ORIGINAL_NAME);
+            final Config.Observable config = savedInstanceState.getParcelable(KEY_LOCAL_CONFIG);
+            final String originalName = savedInstanceState.getString(KEY_ORIGINAL_NAME);
             if (tunnel != null && !tunnel.getName().equals(originalName))
                 onSelectedTunnelChanged(null, tunnel);
             else
diff --git a/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java b/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
index 2b81a98a..9fc7346b 100644
--- a/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
+++ b/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
@@ -43,6 +43,7 @@ import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.zip.ZipEntry;
@@ -82,7 +83,7 @@ public class TunnelListFragment extends BaseFragment {
             return;
         final ContentResolver contentResolver = activity.getContentResolver();
 
-        final List<CompletableFuture<Tunnel>> futureTunnels = new ArrayList<>();
+        final Collection<CompletableFuture<Tunnel>> futureTunnels = new ArrayList<>();
         final List<Throwable> throwables = new ArrayList<>();
         asyncWorker.supplyAsync(() -> {
             final String[] columns = {OpenableColumns.DISPLAY_NAME};
@@ -106,31 +107,32 @@ public class TunnelListFragment extends BaseFragment {
                 throw new IllegalArgumentException("File must be .conf or .zip");
 
             if (isZip) {
-                ZipInputStream zip = new ZipInputStream(contentResolver.openInputStream(uri));
-                BufferedReader reader = new BufferedReader(new InputStreamReader(zip, StandardCharsets.UTF_8));
-                ZipEntry entry;
-                while ((entry = zip.getNextEntry()) != null) {
-                    if (entry.isDirectory())
-                        continue;
-                    name = entry.getName();
-                    idx = name.lastIndexOf('/');
-                    if (idx >= 0) {
-                        if (idx >= name.length() - 1)
+                try (ZipInputStream zip = new ZipInputStream(contentResolver.openInputStream(uri))) {
+                    BufferedReader reader = new BufferedReader(new InputStreamReader(zip, StandardCharsets.UTF_8));
+                    ZipEntry entry;
+                    while ((entry = zip.getNextEntry()) != null) {
+                        if (entry.isDirectory())
                             continue;
-                        name = name.substring(name.lastIndexOf('/') + 1);
-                    }
-                    if (name.toLowerCase().endsWith(".conf"))
-                        name = name.substring(0, name.length() - ".conf".length());
-                    else
-                        continue;
-                    Config config = null;
-                    try {
-                        config = Config.from(reader);
-                    } catch (Exception e) {
-                        throwables.add(e);
+                        name = entry.getName();
+                        idx = name.lastIndexOf('/');
+                        if (idx >= 0) {
+                            if (idx >= name.length() - 1)
+                                continue;
+                            name = name.substring(name.lastIndexOf('/') + 1);
+                        }
+                        if (name.toLowerCase().endsWith(".conf"))
+                            name = name.substring(0, name.length() - ".conf".length());
+                        else
+                            continue;
+                        Config config = null;
+                        try {
+                            config = Config.from(reader);
+                        } catch (Exception e) {
+                            throwables.add(e);
+                        }
+                        if (config != null)
+                            futureTunnels.add(tunnelManager.create(name, config).toCompletableFuture());
                     }
-                    if (config != null)
-                        futureTunnels.add(tunnelManager.create(name, config).toCompletableFuture());
                 }
             } else {
                 futureTunnels.add(tunnelManager.create(name, Config.from(contentResolver.openInputStream(uri))).toCompletableFuture());
@@ -146,15 +148,15 @@ public class TunnelListFragment extends BaseFragment {
             return CompletableFuture.allOf(futureTunnels.toArray(new CompletableFuture[futureTunnels.size()]));
         }).whenComplete((future, exception) -> {
             if (exception != null) {
-                this.onTunnelImportFinished(Collections.emptyList(), Collections.singletonList(exception));
+                onTunnelImportFinished(Collections.emptyList(), Collections.singletonList(exception));
             } else {
                 future.whenComplete((ignored1, ignored2) -> {
-                    ArrayList<Tunnel> tunnels = new ArrayList<>(futureTunnels.size());
-                    for (CompletableFuture<Tunnel> futureTunnel : futureTunnels) {
+                    final List<Tunnel> tunnels = new ArrayList<>(futureTunnels.size());
+                    for (final CompletableFuture<Tunnel> futureTunnel : futureTunnels) {
                         Tunnel tunnel = null;
                         try {
                             tunnel = futureTunnel.getNow(null);
-                        } catch (Exception e) {
+                        } catch (final Exception e) {
                             throwables.add(e);
                         }
                         if (tunnel != null)
@@ -240,7 +242,7 @@ public class TunnelListFragment extends BaseFragment {
         }
     }
 
-    private void onTunnelImportFinished(final List<Tunnel> tunnels, final List<Throwable> throwables) {
+    private void onTunnelImportFinished(final List<Tunnel> tunnels, final Collection<Throwable> throwables) {
         String message = null;
 
         for (final Throwable throwable : throwables) {
diff --git a/app/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java b/app/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java
index b10d8388..677c56c9 100644
--- a/app/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java
+++ b/app/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java
@@ -22,6 +22,7 @@ import com.wireguard.config.Config;
 
 import java.io.File;
 import java.io.FileOutputStream;
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
@@ -39,7 +40,7 @@ public class ZipExporterPreference extends Preference {
 
     private final AsyncWorker asyncWorker;
     private final TunnelManager tunnelManager;
-    private String exportedFilePath = null;
+    private String exportedFilePath;
 
     @SuppressWarnings({"SameParameterValue", "WeakerAccess"})
     public ZipExporterPreference(final Context context, final AttributeSet attrs) {
@@ -49,9 +50,19 @@ public class ZipExporterPreference extends Preference {
         tunnelManager = applicationComponent.getTunnelManager();
     }
 
+    private static SettingsActivity getPrefActivity(final Preference preference) {
+        final Context context = preference.getContext();
+        if (context instanceof ContextThemeWrapper) {
+            if (((ContextThemeWrapper) context).getBaseContext() instanceof SettingsActivity) {
+                return ((SettingsActivity) ((ContextThemeWrapper) context).getBaseContext());
+            }
+        }
+        return null;
+    }
+
     private void exportZip() {
-        List<Tunnel> tunnels = new ArrayList<>(tunnelManager.getTunnels());
-        List<CompletableFuture<Config>> futureConfigs = new ArrayList<>(tunnels.size());
+        final List<Tunnel> tunnels = new ArrayList<>(tunnelManager.getTunnels());
+        final List<CompletableFuture<Config>> futureConfigs = new ArrayList<>(tunnels.size());
         for (final Tunnel tunnel : tunnels)
             futureConfigs.add(tunnel.getConfigAsync().toCompletableFuture());
         if (futureConfigs.isEmpty()) {
@@ -65,9 +76,9 @@ public class ZipExporterPreference extends Preference {
                             throw exception;
                         final File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
                         final File file = new File(path, "wireguard-export.zip");
-                        try {
-                            path.mkdirs();
-                            final ZipOutputStream zip = new ZipOutputStream(new FileOutputStream(file));
+                        if (!path.mkdirs())
+                            throw new IOException("Cannot create output directory");
+                        try (ZipOutputStream zip = new ZipOutputStream(new FileOutputStream(file))) {
                             for (int i = 0; i < futureConfigs.size(); ++i) {
                                 zip.putNextEntry(new ZipEntry(tunnels.get(i).getName() + ".conf"));
                                 zip.write(futureConfigs.get(i).getNow(null).
@@ -76,6 +87,7 @@ public class ZipExporterPreference extends Preference {
                             zip.closeEntry();
                             zip.close();
                         } catch (Exception e) {
+                            // noinspection ResultOfMethodCallIgnored
                             file.delete();
                             throw e;
                         }
@@ -84,7 +96,7 @@ public class ZipExporterPreference extends Preference {
                 });
     }
 
-    private void exportZipComplete(String filePath, Throwable throwable) {
+    private void exportZipComplete(final String filePath, final Throwable throwable) {
         if (throwable != null) {
             final String error = ExceptionLoggers.unwrap(throwable).getMessage();
             final String message = getContext().getString(R.string.export_error, error);
@@ -99,16 +111,6 @@ public class ZipExporterPreference extends Preference {
         }
     }
 
-    private SettingsActivity getPrefActivity(Preference preference) {
-        Context context = preference.getContext();
-        if (context instanceof ContextThemeWrapper) {
-            if (((ContextThemeWrapper) context).getBaseContext() instanceof SettingsActivity) {
-                return ((SettingsActivity) ((ContextThemeWrapper) context).getBaseContext());
-            }
-        }
-        return null;
-    }
-
     @Override
     public CharSequence getSummary() {
         if (exportedFilePath == null)