Disabled Jack

I'd love to use Java 8 features, but Jack just isn't ready yet.

app/build.gradle

@@ -20,11 +20,11 @@ android {
         targetSdkVersion 25
         versionCode 9
         versionName "1.0-beta9"
-        jackOptions.enabled = true
+        jackOptions.enabled = false
     }
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_8
+        sourceCompatibility JavaVersion.VERSION_1_7
-        targetCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_7
     }
     buildTypes {
         release {

app/src/main/java/ch/dissem/apps/abit/AbstractItemListFragment.java

@@ -37,7 +37,12 @@ public abstract class AbstractItemListFragment<T> extends ListFragment implement
      * A dummy implementation of the {@link ListSelectionListener} interface that does
      * nothing. Used only when this fragment is not attached to an activity.
      */
-    private static final ListSelectionListener<Object> dummyCallbacks = plaintext -> {
+    private static final ListSelectionListener<Object> dummyCallbacks =
+        new ListSelectionListener<Object>() {
+            @Override
+            public void onItemSelected(Object item) {
+                // NO OP
+            }
         };
     /**
      * The fragment's current callback object, which is notified of list item

app/src/main/java/ch/dissem/apps/abit/AddressDetailFragment.java

@@ -18,6 +18,7 @@ package ch.dissem.apps.abit;
 
 import android.app.Activity;
 import android.app.AlertDialog;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.graphics.Bitmap;
 import android.os.Bundle;
@@ -31,6 +32,7 @@ import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.CompoundButton;
 import android.widget.ImageView;
 import android.widget.Switch;
 import android.widget.TextView;
@@ -137,7 +139,9 @@ public class AddressDetailFragment extends Fragment {
                     warning = R.string.delete_contact_warning;
                 new AlertDialog.Builder(ctx)
                     .setMessage(warning)
-                    .setPositiveButton(android.R.string.yes, (dialog, which) -> {
+                    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
                             Singleton.getAddressRepository(ctx).remove(item);
                             MainActivity mainActivity = MainActivity.getInstance();
                             if (item.getPrivateKey() != null && mainActivity != null) {
@@ -145,6 +149,7 @@ public class AddressDetailFragment extends Fragment {
                             }
                             item = null;
                             ctx.onBackPressed();
+                        }
                     })
                     .setNegativeButton(android.R.string.no, null)
                     .show();
@@ -153,7 +158,9 @@ public class AddressDetailFragment extends Fragment {
             case R.id.export: {
                 new AlertDialog.Builder(ctx)
                     .setMessage(R.string.confirm_export)
-                    .setPositiveButton(android.R.string.yes, (dialog, which) -> {
+                    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
                             Intent shareIntent = new Intent(Intent.ACTION_SEND);
                             shareIntent.setType("text/plain");
                             shareIntent.putExtra(Intent.EXTRA_TITLE, item +
@@ -164,6 +171,7 @@ public class AddressDetailFragment extends Fragment {
                             shareIntent.putExtra(Intent.EXTRA_TEXT, exporter.toString
                                 ());
                             startActivity(Intent.createChooser(shareIntent, null));
+                        }
                     })
                     .setNegativeButton(android.R.string.no, null)
                     .show();
@@ -225,8 +233,12 @@ public class AddressDetailFragment extends Fragment {
             if (item.getPrivateKey() == null) {
                 Switch active = (Switch) rootView.findViewById(R.id.active);
                 active.setChecked(item.isSubscribed());
-                active.setOnCheckedChangeListener((buttonView, isChecked) ->
+                active.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
-                    item.setSubscribed(isChecked));
+                    @Override
+                    public void onCheckedChanged(CompoundButton button, boolean checked) {
+                        item.setSubscribed(checked);
+                    }
+                });
 
                 ImageView pubkeyAvailableImg = (ImageView) rootView.findViewById(R.id
                     .pubkey_available);

app/src/main/java/ch/dissem/apps/abit/AddressListFragment.java

@@ -33,6 +33,7 @@ import android.widget.TextView;
 import com.google.zxing.integration.android.IntentIntegrator;
 
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
 
 import ch.dissem.apps.abit.listener.ActionBarListener;
@@ -56,7 +57,9 @@ public class AddressListFragment extends AbstractItemListFragment<BitmessageAddr
     public void updateList() {
         List<BitmessageAddress> addresses = Singleton.getAddressRepository(getContext())
             .getContacts();
-        Collections.sort(addresses, (lhs, rhs) -> {
+        Collections.sort(addresses, new Comparator<BitmessageAddress>() {
+            @Override
+            public int compare(BitmessageAddress lhs, BitmessageAddress rhs) {
                 // Yields the following order:
                 // * Subscribed addresses come first
                 // * Addresses with Aliases (alphabetically)
@@ -79,6 +82,7 @@ public class AddressListFragment extends AbstractItemListFragment<BitmessageAddr
                 } else {
                     return 1;
                 }
+            }
         });
         setListAdapter(new ArrayAdapter<BitmessageAddress>(
             getActivity(),

app/src/main/java/ch/dissem/apps/abit/ComposeMessageFragment.java

@@ -96,7 +96,12 @@ public class ComposeMessageFragment extends Fragment {
             final ContactAdapter adapter = new ContactAdapter(getContext());
             recipientInput.setAdapter(adapter);
             recipientInput.setOnItemClickListener(
-                (parent, view, position, id) -> recipient = adapter.getItem(position)
+                new AdapterView.OnItemClickListener() {
+                    @Override
+                    public void onItemClick(AdapterView<?> parent, View view, int pos, long id) {
+                        adapter.getItem(pos);
+                    }
+                }
             );
             recipientInput.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                 @Override

app/src/main/java/ch/dissem/apps/abit/CreateAddressActivity.java

@@ -20,6 +20,7 @@ import android.app.Activity;
 import android.net.Uri;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
+import android.view.View;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.Switch;
@@ -60,12 +61,17 @@ public class CreateAddressActivity extends AppCompatActivity {
         }
 
         final Button cancel = (Button) findViewById(R.id.cancel);
-        cancel.setOnClickListener(v -> {
+        cancel.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
                 setResult(Activity.RESULT_CANCELED);
                 finish();
+            }
         });
         final Button ok = (Button) findViewById(R.id.do_import);
-        ok.setOnClickListener(v -> {
+        ok.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
                 String addressText = String.valueOf(address.getText()).trim();
                 try {
                     BitmessageAddress bmAddress = new BitmessageAddress(addressText);
@@ -83,6 +89,7 @@ public class CreateAddressActivity extends AppCompatActivity {
                 } catch (RuntimeException e) {
                     address.setError(getString(R.string.error_illegal_address));
                 }
+            }
         });
     }
 

app/src/main/java/ch/dissem/apps/abit/ImportIdentitiesFragment.java

@@ -67,7 +67,9 @@ public class ImportIdentitiesFragment extends Fragment {
         } catch (IOException e) {
             return super.onCreateView(inflater, container, savedInstanceState);
         }
-        view.findViewById(R.id.finish).setOnClickListener(v -> {
+        view.findViewById(R.id.finish).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
                 importer.importAll(adapter.getSelected());
                 MainActivity mainActivity = MainActivity.getInstance();
                 if (mainActivity != null) {
@@ -76,6 +78,7 @@ public class ImportIdentitiesFragment extends Fragment {
                     }
                 }
                 getActivity().finish();
+            }
         });
         return view;
     }

app/src/main/java/ch/dissem/apps/abit/InputWifFragment.java

@@ -28,6 +28,7 @@ import android.view.ViewGroup;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import com.github.angads25.filepicker.controller.DialogSelectionListener;
 import com.github.angads25.filepicker.model.DialogConfigs;
 import com.github.angads25.filepicker.model.DialogProperties;
 import com.github.angads25.filepicker.view.FilePickerDialog;
@@ -60,7 +61,9 @@ public class InputWifFragment extends Fragment {
         View view = inflater.inflate(R.layout.fragment_import_input, container, false);
         wifData = (TextView) view.findViewById(R.id.wif_input);
 
-        view.findViewById(R.id.next).setOnClickListener(v -> {
+        view.findViewById(R.id.next).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
                 Bundle bundle = new Bundle();
                 bundle.putString(WIF_DATA, wifData.getText().toString());
 
@@ -70,6 +73,7 @@ public class InputWifFragment extends Fragment {
                 getFragmentManager().beginTransaction()
                     .replace(R.id.content, fragment)
                     .commit();
+            }
         });
         return view;
     }
@@ -89,7 +93,9 @@ public class InputWifFragment extends Fragment {
         properties.extensions = null;
         FilePickerDialog dialog = new FilePickerDialog(getActivity(), properties);
         dialog.setTitle(getString(R.string.select_file_title));
-        dialog.setDialogSelectionListener(files -> {
+        dialog.setDialogSelectionListener(new DialogSelectionListener() {
+            @Override
+            public void onSelectedFilePaths(String[] files) {
                 if (files.length > 0) {
                     try (InputStream in = new FileInputStream(files[0])) {
                         ByteArrayOutputStream data = new ByteArrayOutputStream();
@@ -108,6 +114,7 @@ public class InputWifFragment extends Fragment {
                         ).show();
                     }
                 }
+            }
         });
         dialog.show();
         return true;

app/src/main/java/ch/dissem/apps/abit/MainActivity.java

@@ -24,10 +24,12 @@ import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.CompoundButton;
 import android.widget.RelativeLayout;
 import android.widget.Toast;
 
 import com.github.amlcurran.showcaseview.ShowcaseView;
+import com.github.amlcurran.showcaseview.targets.Target;
 import com.mikepenz.community_material_typeface_library.CommunityMaterial;
 import com.mikepenz.google_material_typeface_library.GoogleMaterial;
 import com.mikepenz.iconics.IconicsDrawable;
@@ -35,6 +37,7 @@ import com.mikepenz.materialdrawer.AccountHeader;
 import com.mikepenz.materialdrawer.AccountHeaderBuilder;
 import com.mikepenz.materialdrawer.Drawer;
 import com.mikepenz.materialdrawer.DrawerBuilder;
+import com.mikepenz.materialdrawer.interfaces.OnCheckedChangeListener;
 import com.mikepenz.materialdrawer.model.DividerDrawerItem;
 import com.mikepenz.materialdrawer.model.PrimaryDrawerItem;
 import com.mikepenz.materialdrawer.model.ProfileDrawerItem;
@@ -182,13 +185,16 @@ public class MainActivity extends AppCompatActivity
                 .setStyle(R.style.CustomShowcaseTheme)
                 .setContentTitle(R.string.full_node)
                 .setContentText(R.string.full_node_description)
-                .setTarget(() -> {
+                .setTarget(new Target() {
+                    @Override
+                    public Point getPoint() {
                         View view = drawer.getStickyFooter();
                         int[] location = new int[2];
                         view.getLocationInWindow(location);
                         int x = location[0] + 7 * view.getWidth() / 8;
                         int y = location[1] + view.getHeight() / 2;
                         return new Point(x, y);
+                    }
                 })
                 .replaceEndButton(R.layout.showcase_button)
                 .hideOnTouchOutside()
@@ -246,15 +252,18 @@ public class MainActivity extends AppCompatActivity
             .withActivity(this)
             .withHeaderBackground(R.drawable.header)
             .withProfiles(profiles)
-            .withOnAccountHeaderListener((view, profile, currentProfile) -> {
+            .withOnAccountHeaderListener(new AccountHeader.OnAccountHeaderListener() {
+                @Override
+                public boolean onProfileChanged(View view, IProfile profile, boolean current) {
                     switch ((int) profile.getIdentifier()) {
                         case ADD_IDENTITY:
                             addIdentityDialog();
                             break;
                         case MANAGE_IDENTITY:
-                        BitmessageAddress identity = Singleton.getIdentity(this);
+                            BitmessageAddress identity = Singleton.getIdentity(MainActivity.this);
                             if (identity == null) {
-                            Toast.makeText(this, R.string.no_identity_warning, LENGTH_LONG).show();
+                                Toast.makeText(MainActivity.this,
+                                    R.string.no_identity_warning, LENGTH_LONG).show();
                             } else {
                                 Intent show = new Intent(MainActivity.this,
                                     AddressDetailActivity.class);
@@ -272,6 +281,7 @@ public class MainActivity extends AppCompatActivity
                     }
                     // false if it should close the drawer
                     return false;
+                }
             })
             .build();
         if (profiles.size() > 2) { // There's always the add and manage identity items
@@ -333,11 +343,15 @@ public class MainActivity extends AppCompatActivity
             .withName(R.string.full_node)
             .withIcon(CommunityMaterial.Icon.cmd_cloud_outline)
             .withChecked(isRunning())
-            .withOnCheckedChangeListener((drawerItem, buttonView, isChecked) -> {
+            .withOnCheckedChangeListener(new OnCheckedChangeListener() {
+                @Override
+                public void onCheckedChanged(IDrawerItem drawerItem, CompoundButton buttonView,
+                                             boolean isChecked) {
                     if (isChecked) {
                         checkAndStartNode();
                     } else {
-                    stopService(new Intent(this, BitmessageService.class));
+                        stopService(new Intent(MainActivity.this, BitmessageService.class));
+                    }
                 }
             });
 
@@ -347,7 +361,9 @@ public class MainActivity extends AppCompatActivity
             .withAccountHeader(accountHeader)
             .withDrawerItems(drawerItems)
             .addStickyDrawerItems(nodeSwitch)
-            .withOnDrawerItemClickListener((view, position, item) -> {
+            .withOnDrawerItemClickListener(new Drawer.OnDrawerItemClickListener() {
+                @Override
+                public boolean onItemClick(View view, int position, IDrawerItem item) {
                     if (item.getTag() instanceof Label) {
                         selectedLabel = (Label) item.getTag();
                         showSelectedLabel();
@@ -377,6 +393,7 @@ public class MainActivity extends AppCompatActivity
                         }
                     }
                     return false;
+                }
             })
             .withShowDrawerOnFirstLaunch(true)
             .build();
@@ -461,11 +478,14 @@ public class MainActivity extends AppCompatActivity
     }
 
     public static void updateNodeSwitch() {
-        MainActivity i = getInstance();
+        final MainActivity i = getInstance();
         if (i != null) {
-            i.runOnUiThread(() -> {
+            i.runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
                     i.nodeSwitch.withChecked(i.bmc.isRunning());
                     i.drawer.updateStickyFooterItem(i.nodeSwitch);
+                }
             });
         }
     }

app/src/main/java/ch/dissem/apps/abit/MessageDetailFragment.java

@@ -31,6 +31,7 @@ import android.widget.TextView;
 import com.mikepenz.google_material_typeface_library.GoogleMaterial;
 
 import java.util.Iterator;
+import java.util.regex.Matcher;
 
 import ch.dissem.apps.abit.listener.ActionBarListener;
 import ch.dissem.apps.abit.service.Singleton;
@@ -110,7 +111,12 @@ public class MessageDetailFragment extends Fragment {
 
             Linkify.addLinks(messageBody, WEB_URLS);
             Linkify.addLinks(messageBody, BITMESSAGE_ADDRESS_PATTERN, BITMESSAGE_URL_SCHEMA, null,
-                (match, url) -> match.group()
+                new Linkify.TransformFilter() {
+                    @Override
+                    public String transformUrl(Matcher match, String url) {
+                        return match.group();
+                    }
+                }
             );
 
             messageBody.setLinksClickable(true);

app/src/main/java/ch/dissem/apps/abit/SettingsFragment.java

@@ -46,7 +46,9 @@ public class SettingsFragment
         addPreferencesFromResource(R.xml.preferences);
 
         Preference about = findPreference("about");
-        about.setOnPreferenceClickListener(preference -> {
+        about.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+            @Override
+            public boolean onPreferenceClick(Preference preference) {
                 new LibsBuilder()
                     .withActivityTitle(getActivity().getString(R.string.about))
                     .withActivityStyle(Libs.ActivityStyle.LIGHT_DARK_TOOLBAR)
@@ -55,12 +57,16 @@ public class SettingsFragment
                     .withAboutDescription(getString(R.string.about_app))
                     .start(getActivity());
                 return true;
+            }
         });
 
         Preference status = findPreference("status");
-        status.setOnPreferenceClickListener(preference -> {
+        status.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+            @Override
+            public boolean onPreferenceClick(Preference preference) {
                 startActivity(new Intent(getActivity(), StatusActivity.class));
                 return true;
+            }
         });
     }
 

app/src/main/java/ch/dissem/apps/abit/adapter/AddressSelectorAdapter.java

@@ -21,6 +21,7 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.CheckBox;
+import android.widget.CompoundButton;
 import android.widget.TextView;
 
 import java.util.ArrayList;
@@ -75,10 +76,13 @@ public class AddressSelectorAdapter
             super(v);
             checkbox = (CheckBox) v.findViewById(R.id.checkbox);
             address = (TextView) v.findViewById(R.id.address);
-            checkbox.setOnCheckedChangeListener((buttonView, isChecked) -> {
+            checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+                @Override
+                public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
                     if (data != null) {
                         data.selected = isChecked;
                     }
+                }
             });
         }
     }

app/src/main/java/ch/dissem/apps/abit/adapter/SwipeableMessageAdapter.java

@@ -105,8 +105,18 @@ public class SwipeableMessageAdapter
     }
 
     public SwipeableMessageAdapter() {
-        itemViewOnClickListener = this::onItemViewClick;
+        itemViewOnClickListener = new View.OnClickListener() {
-        swipeableViewContainerOnClickListener = this::onSwipeableViewContainerClick;
+            @Override
+            public void onClick(View view) {
+                onItemViewClick(view);
+            }
+        };
+        swipeableViewContainerOnClickListener = new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                onSwipeableViewContainerClick(view);
+            }
+        };
 
         // SwipeableItemAdapter requires stable ID, and also
         // have to implement the getItemId() method appropriately.

app/src/main/java/ch/dissem/apps/abit/dialog/AddIdentityDialogFragment.java

@@ -19,6 +19,7 @@ package ch.dissem.apps.abit.dialog;
 import android.annotation.SuppressLint;
 import android.app.AlertDialog;
 import android.content.Context;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.os.AsyncTask;
 import android.os.Bundle;
@@ -60,7 +61,9 @@ public class AddIdentityDialogFragment extends AppCompatDialogFragment {
         getDialog().setTitle(R.string.add_identity);
         View view = inflater.inflate(R.layout.dialog_add_identity, container, false);
         final RadioGroup radioGroup = (RadioGroup) view.findViewById(R.id.radioGroup);
-        view.findViewById(R.id.ok).setOnClickListener(v -> {
+        view.findViewById(R.id.ok).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
                 final Context ctx = getActivity().getBaseContext();
                 switch (radioGroup.getCheckedRadioButtonId()) {
                     case R.id.create_identity:
@@ -99,8 +102,14 @@ public class AddIdentityDialogFragment extends AppCompatDialogFragment {
                         return;
                 }
                 dismiss();
+            }
+        });
+        view.findViewById(R.id.dismiss).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                dismiss();
+            }
         });
-        view.findViewById(R.id.dismiss).setOnClickListener(v -> dismiss());
         return view;
     }
 
@@ -113,7 +122,9 @@ public class AddIdentityDialogFragment extends AppCompatDialogFragment {
         new AlertDialog.Builder(activity)
             .setTitle(R.string.add_chan)
             .setView(dialogView)
-            .setPositiveButton(R.string.ok, (dialogInterface, i) -> {
+            .setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
+                @Override
+                public void onClick(DialogInterface dialogInterface, int i) {
                     TextView passphrase = (TextView) dialogView.findViewById(R.id.passphrase);
                     Toast.makeText(ctx, R.string.toast_long_running_operation,
                         Toast.LENGTH_SHORT).show();
@@ -138,6 +149,7 @@ public class AddIdentityDialogFragment extends AppCompatDialogFragment {
                             }
                         }
                     }.execute(passphrase.getText().toString());
+                }
             })
             .setNegativeButton(R.string.cancel, null)
             .show();

app/src/main/java/ch/dissem/apps/abit/dialog/DeterministicIdentityDialogFragment.java

@@ -56,10 +56,13 @@ public class DeterministicIdentityDialogFragment extends AppCompatDialogFragment
         getDialog().setTitle(R.string.add_deterministic_address);
         View view = inflater.inflate(R.layout.dialog_add_deterministic_identity, container, false);
         view.findViewById(R.id.ok)
-            .setOnClickListener(v -> {
+            .setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View view) {
                     dismiss();
                     final Context context = getActivity().getBaseContext();
                     View dialogView = getView();
+                    assert dialogView != null;
                     TextView label = (TextView) dialogView.findViewById(R.id.label);
                     TextView passphrase = (TextView) dialogView.findViewById(R.id.passphrase);
                     TextView numberOfAddresses = (TextView) dialogView.findViewById(R.id
@@ -115,9 +118,14 @@ public class DeterministicIdentityDialogFragment extends AppCompatDialogFragment
                         Integer.valueOf(numberOfAddresses.getText().toString()),
                         shorter.isChecked()
                     );
+                }
+            });
+        view.findViewById(R.id.dismiss).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                dismiss();
+            }
         });
-        view.findViewById(R.id.dismiss)
-            .setOnClickListener(v -> dismiss());
         return view;
     }
 

app/src/main/java/ch/dissem/apps/abit/dialog/FullNodeDialogActivity.java

@@ -19,6 +19,7 @@ package ch.dissem.apps.abit.dialog;
 import android.app.Activity;
 import android.content.Intent;
 import android.os.Bundle;
+import android.view.View;
 
 import ch.dissem.apps.abit.R;
 import ch.dissem.apps.abit.service.BitmessageService;
@@ -34,11 +35,19 @@ public class FullNodeDialogActivity extends Activity {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.dialog_full_node);
-        findViewById(R.id.ok).setOnClickListener(v -> {
+        findViewById(R.id.ok).setOnClickListener(new View.OnClickListener() {
-            startService(new Intent(this, BitmessageService.class));
+            @Override
+            public void onClick(View view) {
+                startService(new Intent(FullNodeDialogActivity.this, BitmessageService.class));
                 updateNodeSwitch();
                 finish();
+            }
+        });
+        findViewById(R.id.dismiss).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                finish();
+            }
         });
-        findViewById(R.id.dismiss).setOnClickListener(v -> finish());
     }
 }

app/src/main/java/ch/dissem/apps/abit/listener/MessageListener.java

@@ -48,7 +48,9 @@ public class MessageListener implements BitmessageContext.Listener {
 
     @Override
     public void receive(final Plaintext plaintext) {
-        pool.submit(() -> {
+        pool.submit(new Runnable() {
+            @Override
+            public void run() {
                 unacknowledged.addFirst(plaintext);
                 numberOfUnacknowledgedMessages++;
                 if (unacknowledged.size() > 5) {
@@ -66,14 +68,18 @@ public class MessageListener implements BitmessageContext.Listener {
                 if (main != null) {
                     main.updateUnread();
                 }
+            }
         });
     }
 
     public void resetNotification() {
-        pool.submit(() -> {
+        pool.submit(new Runnable() {
+            @Override
+            public void run() {
                 notification.hide();
                 unacknowledged.clear();
                 numberOfUnacknowledgedMessages = 0;
+            }
         });
     }
 }

app/src/main/java/ch/dissem/apps/abit/pow/ServerPowEngine.java

@@ -17,12 +17,14 @@
 package ch.dissem.apps.abit.pow;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
 
 import ch.dissem.apps.abit.service.Singleton;
 import ch.dissem.apps.abit.synchronization.SyncAdapter;
@@ -50,16 +52,21 @@ public class ServerPowEngine implements ProofOfWorkEngine, InternalContext
 
     public ServerPowEngine(Context ctx) {
         this.ctx = ctx;
-        pool = Executors.newCachedThreadPool(r -> {
+        pool = Executors.newCachedThreadPool(new ThreadFactory() {
+            @Override
+            public Thread newThread(@NonNull Runnable r) {
                 Thread thread = Executors.defaultThreadFactory().newThread(r);
                 thread.setPriority(Thread.MIN_PRIORITY);
                 return thread;
+            }
         });
     }
 
     @Override
     public void calculateNonce(final byte[] initialHash, final byte[] target, Callback callback) {
-        pool.execute(() -> {
+        pool.execute(new Runnable() {
+            @Override
+            public void run() {
                 BitmessageAddress identity = Singleton.getIdentity(ctx);
                 if (identity == null) throw new RuntimeException("No Identity for calculating POW");
 
@@ -79,6 +86,7 @@ public class ServerPowEngine implements ProofOfWorkEngine, InternalContext
                 } catch (Exception e) {
                     LOG.error(e.getMessage(), e);
                 }
+            }
         });
     }
 

app/src/main/java/ch/dissem/apps/abit/service/ProofOfWorkService.java

@@ -92,7 +92,9 @@ public class ProofOfWorkService extends Service {
     }
 
     private void calculateNonce(final PowItem item) {
-        engine.calculateNonce(item.initialHash, item.targetValue, (initialHash, nonce) -> {
+        engine.calculateNonce(item.initialHash, item.targetValue, new ProofOfWorkEngine.Callback() {
+            @Override
+            public void onNonceCalculated(byte[] initialHash, byte[] nonce) {
                 try {
                     item.callback.onNonceCalculated(initialHash, nonce);
                 } finally {
@@ -111,6 +113,7 @@ public class ProofOfWorkService extends Service {
                         calculateNonce(next);
                     }
                 }
+            }
         });
     }
 }

app/src/main/java/ch/dissem/apps/abit/service/Singleton.java

@@ -110,9 +110,9 @@ public class Singleton {
         return powRepo;
     }
 
-    public static BitmessageAddress getIdentity(Context ctx) {
+    public static BitmessageAddress getIdentity(final Context ctx) {
         if (identity == null) {
-            BitmessageContext bmc = getBitmessageContext(ctx);
+            final BitmessageContext bmc = getBitmessageContext(ctx);
             synchronized (Singleton.class) {
                 if (identity == null) {
                     List<BitmessageAddress> identities = bmc.addresses()