Use try-with-resources.

app/src/main/java/org/schabi/newpipe/about/LicenseFragmentHelper.java

@@ -37,14 +37,12 @@ public final class LicenseFragmentHelper {
                                               @NonNull final License license) {
         final StringBuilder licenseContent = new StringBuilder();
         final String webViewData;
-        try {
+        try (BufferedReader in = new BufferedReader(new InputStreamReader(
-            final BufferedReader in = new BufferedReader(new InputStreamReader(
+                context.getAssets().open(license.getFilename()), StandardCharsets.UTF_8))) {
-                    context.getAssets().open(license.getFilename()), StandardCharsets.UTF_8));
             String str;
             while ((str = in.readLine()) != null) {
                 licenseContent.append(str);
             }
-            in.close();
 
             // split the HTML file and insert the stylesheet into the HEAD of the file
             webViewData = licenseContent.toString().replace("</head>",

app/src/main/java/org/schabi/newpipe/settings/ContentSettingsFragment.java

@@ -212,15 +212,14 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
             //checkpoint before export
             NewPipeDatabase.checkpoint();
 
-            final ZipOutputStream outZip = new ZipOutputStream(
+            try (ZipOutputStream outZip = new ZipOutputStream(new BufferedOutputStream(
-                    new BufferedOutputStream(
+                            new FileOutputStream(path)))) {
-                            new FileOutputStream(path)));
+                ZipHelper.addFileToZip(outZip, newpipeDb.getPath(), "newpipe.db");
-            ZipHelper.addFileToZip(outZip, newpipeDb.getPath(), "newpipe.db");
 
-            saveSharedPreferencesToFile(newpipeSettings);
+                saveSharedPreferencesToFile(newpipeSettings);
-            ZipHelper.addFileToZip(outZip, newpipeSettings.getPath(), "newpipe.settings");
+                ZipHelper.addFileToZip(outZip, newpipeSettings.getPath(),
-
+                        "newpipe.settings");
-            outZip.close();
+            }
 
             Toast.makeText(getContext(), R.string.export_complete_toast, Toast.LENGTH_SHORT)
                     .show();
@@ -230,41 +229,23 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
     }
 
     private void saveSharedPreferencesToFile(final File dst) {
-        ObjectOutputStream output = null;
+        try (ObjectOutputStream output = new ObjectOutputStream(new FileOutputStream(dst))) {
-        try {
-            output = new ObjectOutputStream(new FileOutputStream(dst));
             final SharedPreferences pref
                     = PreferenceManager.getDefaultSharedPreferences(requireContext());
             output.writeObject(pref.getAll());
-
+            output.flush();
         } catch (final IOException e) {
             e.printStackTrace();
-        } finally {
-            try {
-                if (output != null) {
-                    output.flush();
-                    output.close();
-                }
-            } catch (final IOException ex) {
-                ex.printStackTrace();
-            }
         }
     }
 
     private void importDatabase(final String filePath) {
         // check if file is supported
-        ZipFile zipFile = null;
+        try (ZipFile zipFile = new ZipFile(filePath)) {
-        try {
-            zipFile = new ZipFile(filePath);
         } catch (final IOException ioe) {
             Toast.makeText(getContext(), R.string.no_valid_zip_file, Toast.LENGTH_SHORT)
                     .show();
             return;
-        } finally {
-            try {
-                zipFile.close();
-            } catch (final Exception ignored) {
-            }
         }
 
         try {
@@ -312,9 +293,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
     }
 
     private void loadSharedPreferences(final File src) {
-        ObjectInputStream input = null;
+        try (ObjectInputStream input = new ObjectInputStream(new FileInputStream(src))) {
-        try {
-            input = new ObjectInputStream(new FileInputStream(src));
             final SharedPreferences.Editor prefEdit = PreferenceManager
                     .getDefaultSharedPreferences(requireContext()).edit();
             prefEdit.clear();
@@ -338,14 +317,6 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
             prefEdit.commit();
         } catch (final IOException | ClassNotFoundException e) {
             e.printStackTrace();
-        } finally {
-            try {
-                if (input != null) {
-                    input.close();
-                }
-            } catch (final IOException ex) {
-                ex.printStackTrace();
-            }
         }
     }
 

app/src/main/java/org/schabi/newpipe/util/StateSaver.java

@@ -34,7 +34,6 @@ import org.schabi.newpipe.MainActivity;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
-import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.util.LinkedList;
@@ -106,7 +105,6 @@ public final class StateSaver {
                     + "writeRead = [" + writeRead + "]");
         }
 
-        FileInputStream fileInputStream = null;
         try {
             Queue<Object> savedObjects
                     = STATE_OBJECTS_HOLDER.remove(savedState.getPrefixFileSaved());
@@ -127,10 +125,12 @@ public final class StateSaver {
                 return null;
             }
 
-            fileInputStream = new FileInputStream(file);
+            try (FileInputStream fileInputStream = new FileInputStream(file);
-            final ObjectInputStream inputStream = new ObjectInputStream(fileInputStream);
+                 ObjectInputStream inputStream = new ObjectInputStream(fileInputStream)) {
-            //noinspection unchecked
+                //noinspection unchecked
-            savedObjects = (Queue<Object>) inputStream.readObject();
+                savedObjects = (Queue<Object>) inputStream.readObject();
+            }
+
             if (savedObjects != null) {
                 writeRead.readFrom(savedObjects);
             }
@@ -138,13 +138,6 @@ public final class StateSaver {
             return savedState;
         } catch (final Exception e) {
             Log.e(TAG, "Failed to restore state", e);
-        } finally {
-            if (fileInputStream != null) {
-                try {
-                    fileInputStream.close();
-                } catch (final IOException ignored) {
-                }
-            }
         }
         return null;
     }
@@ -227,7 +220,6 @@ public final class StateSaver {
             }
         }
 
-        FileOutputStream fileOutputStream = null;
         try {
             File cacheDir = new File(cacheDirPath);
             if (!cacheDir.exists()) {
@@ -258,19 +250,14 @@ public final class StateSaver {
                 }
             }
 
-            fileOutputStream = new FileOutputStream(file);
+            try (FileOutputStream fileOutputStream = new FileOutputStream(file);
-            final ObjectOutputStream outputStream = new ObjectOutputStream(fileOutputStream);
+                 ObjectOutputStream outputStream = new ObjectOutputStream(fileOutputStream)) {
-            outputStream.writeObject(savedObjects);
+                outputStream.writeObject(savedObjects);
+            }
 
             return new SavedState(prefixFileName, file.getAbsolutePath());
         } catch (final Exception e) {
             Log.e(TAG, "Failed to save state", e);
-        } finally {
-            if (fileOutputStream != null) {
-                try {
-                    fileOutputStream.close();
-                } catch (final IOException ignored) { }
-            }
         }
         return null;
     }

app/src/main/java/org/schabi/newpipe/util/ZipHelper.java

@@ -45,15 +45,15 @@ public final class ZipHelper {
     public static void addFileToZip(final ZipOutputStream outZip, final String file,
                                     final String name) throws Exception {
         final byte[] data = new byte[BUFFER_SIZE];
-        final FileInputStream fi = new FileInputStream(file);
+        try (FileInputStream fi = new FileInputStream(file);
-        final BufferedInputStream inputStream = new BufferedInputStream(fi, BUFFER_SIZE);
+             BufferedInputStream inputStream = new BufferedInputStream(fi, BUFFER_SIZE)) {
-        final ZipEntry entry = new ZipEntry(name);
+            final ZipEntry entry = new ZipEntry(name);
-        outZip.putNextEntry(entry);
+            outZip.putNextEntry(entry);
-        int count;
+            int count;
-        while ((count = inputStream.read(data, 0, BUFFER_SIZE)) != -1) {
+            while ((count = inputStream.read(data, 0, BUFFER_SIZE)) != -1) {
-            outZip.write(data, 0, count);
+                outZip.write(data, 0, count);
+            }
         }
-        inputStream.close();
     }
 
     /**
@@ -68,37 +68,35 @@ public final class ZipHelper {
      */
     public static boolean extractFileFromZip(final String filePath, final String file,
                                              final String name) throws Exception {
+        try (ZipInputStream inZip = new ZipInputStream(new BufferedInputStream(
+                new FileInputStream(filePath)))) {
+            final byte[] data = new byte[BUFFER_SIZE];
 
-        final ZipInputStream inZip = new ZipInputStream(
+            boolean found = false;
-                new BufferedInputStream(
-                        new FileInputStream(filePath)));
 
-        final byte[] data = new byte[BUFFER_SIZE];
+            ZipEntry ze;
-
+            while ((ze = inZip.getNextEntry()) != null) {
-        boolean found = false;
+                if (ze.getName().equals(name)) {
-
+                    found = true;
-        ZipEntry ze;
+                    // delete old file first
-        while ((ze = inZip.getNextEntry()) != null) {
+                    final File oldFile = new File(file);
-            if (ze.getName().equals(name)) {
+                    if (oldFile.exists()) {
-                found = true;
+                        if (!oldFile.delete()) {
-                // delete old file first
+                            throw new Exception("Could not delete " + file);
-                final File oldFile = new File(file);
+                        }
-                if (oldFile.exists()) {
-                    if (!oldFile.delete()) {
-                        throw new Exception("Could not delete " + file);
                     }
-                }
 
-                final FileOutputStream outFile = new FileOutputStream(file);
+                    try (FileOutputStream outFile = new FileOutputStream(file)) {
-                int count = 0;
+                        int count = 0;
-                while ((count = inZip.read(data)) != -1) {
+                        while ((count = inZip.read(data)) != -1) {
-                    outFile.write(data, 0, count);
+                            outFile.write(data, 0, count);
-                }
+                        }
+                    }
 
-                outFile.close();
+                    inZip.closeEntry();
-                inZip.closeEntry();
+                }
             }
+            return found;
         }
-        return found;
     }
 }

app/src/main/java/us/shandian/giga/get/DownloadInitializer.java

@@ -147,10 +147,10 @@ public class DownloadInitializer extends Thread {
                     if (!mMission.running || Thread.interrupted()) return;
                 }
 
-                SharpStream fs = mMission.storage.getStream();
+                try (SharpStream fs = mMission.storage.getStream()) {
-                fs.setLength(mMission.offsets[mMission.current] + mMission.length);
+                    fs.setLength(mMission.offsets[mMission.current] + mMission.length);
-                fs.seek(mMission.offsets[mMission.current]);
+                    fs.seek(mMission.offsets[mMission.current]);
-                fs.close();
+                }
 
                 if (!mMission.running || Thread.interrupted()) return;
 

app/src/main/java/us/shandian/giga/postprocessing/Postprocessing.java

@@ -108,7 +108,6 @@ public abstract class Postprocessing implements Serializable {
     public void run(DownloadMission target) throws IOException {
         this.mission = target;
 
-        CircularFileWriter out = null;
         int result;
         long finalLength = -1;
 
@@ -151,30 +150,32 @@ public abstract class Postprocessing implements Serializable {
                         return -1;
                     };
 
-                    out = new CircularFileWriter(mission.storage.getStream(), tempFile, checker);
+                    try (CircularFileWriter out = new CircularFileWriter(
-                    out.onProgress = (long position) -> mission.done = position;
+                            mission.storage.getStream(), tempFile, checker)) {
+                        out.onProgress = (long position) -> mission.done = position;
 
-                    out.onWriteError = (err) -> {
+                        out.onWriteError = err -> {
-                        mission.psState = 3;
+                            mission.psState = 3;
-                        mission.notifyError(ERROR_POSTPROCESSING_HOLD, err);
+                            mission.notifyError(ERROR_POSTPROCESSING_HOLD, err);
 
-                        try {
+                            try {
-                            synchronized (this) {
+                                synchronized (this) {
-                                while (mission.psState == 3)
+                                    while (mission.psState == 3)
-                                    wait();
+                                        wait();
+                                }
+                            } catch (InterruptedException e) {
+                                // nothing to do
+                                Log.e(getClass().getSimpleName(), "got InterruptedException");
                             }
-                        } catch (InterruptedException e) {
-                            // nothing to do
-                            Log.e(this.getClass().getSimpleName(), "got InterruptedException");
-                        }
 
-                        return mission.errCode == ERROR_NOTHING;
+                            return mission.errCode == ERROR_NOTHING;
-                    };
+                        };
 
-                    result = process(out, sources);
+                        result = process(out, sources);
 
-                    if (result == OK_RESULT)
+                        if (result == OK_RESULT)
-                        finalLength = out.finalizeFile();
+                            finalLength = out.finalizeFile();
+                    }
                 } else {
                     result = OK_RESULT;
                 }
@@ -184,9 +185,6 @@ public abstract class Postprocessing implements Serializable {
                         source.close();
                     }
                 }
-                if (out != null) {
-                    out.close();
-                }
                 if (tempFile != null) {
                     //noinspection ResultOfMethodCallIgnored
                     tempFile.delete();

app/src/main/java/us/shandian/giga/util/Utility.java

@@ -80,24 +80,15 @@ public class Utility {
     @SuppressWarnings("unchecked")
     public static <T> T readFromFile(File file) {
         T object;
-        ObjectInputStream objectInputStream = null;
 
-        try {
+        try (ObjectInputStream objectInputStream =
-            objectInputStream = new ObjectInputStream(new FileInputStream(file));
+                     new ObjectInputStream(new FileInputStream(file))) {
             object = (T) objectInputStream.readObject();
         } catch (Exception e) {
             Log.e("Utility", "Failed to deserialize the object", e);
             object = null;
         }
 
-        if (objectInputStream != null) {
-            try {
-                objectInputStream.close();
-            } catch (Exception e) {
-                //nothing to do
-            }
-        }
-
         return object;
     }
 

checkstyle-suppressions.xml

@@ -15,6 +15,10 @@
       files="ListHelper.java"
       lines="281,313"/>
 
+  <suppress checks="EmptyBlock"
+      files="ContentSettingsFragment.java"
+      lines="244,245"/>
+
   <!-- org.schabi.newpipe.streams -->
   <suppress checks="LineLength"
       files="WebMWriter.java"