Use try-with-resources in some places

app/src/main/java/com/topjohnwu/magisk/AboutActivity.java

@@ -63,13 +63,11 @@ public class AboutActivity extends AppCompatActivity {
         appVersionInfo.setSummary(BuildConfig.VERSION_NAME);
 
         String changes = null;
-        try {
+        try (InputStream is = getAssets().open("changelog.html")) {
-            InputStream is = getAssets().open("changelog.html");
             int size = is.available();
 
             byte[] buffer = new byte[size];
             is.read(buffer);
-            is.close();
 
             changes = new String(buffer);
         } catch (IOException ignored) {

app/src/main/java/com/topjohnwu/magisk/LogFragment.java

@@ -182,14 +182,10 @@ public class LogFragment extends Fragment {
 
                     List<String> in = Utils.readFile(MAGISK_LOG);
 
-                    try {
+                    try (FileWriter out = new FileWriter(targetFile)) {
-                        FileWriter out = new FileWriter(targetFile);
                         for (String line : in) {
                             out.write(line + "\n");
                         }
-                        out.close();
-
-
                         return true;
                     } catch (IOException e) {
                         e.printStackTrace();

app/src/main/java/com/topjohnwu/magisk/receivers/RepoDlReceiver.java

@@ -33,9 +33,9 @@ public class RepoDlReceiver extends DownloadReceiver {
                 ZipUtils.signZip(mContext, buffer.getInputStream(), buffer, true);
 
                 // Write it back to the downloaded zip
-                OutputStream out = mContext.getContentResolver().openOutputStream(mUri);
+                try (OutputStream out = mContext.getContentResolver().openOutputStream(mUri)) {
                     buffer.writeTo(out);
-                out.close();
+                }
             }
         }.exec();
     }

app/src/main/java/com/topjohnwu/magisk/utils/Async.java

@@ -194,21 +194,21 @@ public class Async {
 
         protected void copyToCache() throws Throwable {
             publishProgress(mContext.getString(R.string.copying_msg));
-            try {
-                InputStream in = mContext.getContentResolver().openInputStream(mUri);
             mCachedFile = new File(mContext.getCacheDir().getAbsolutePath() + "/install.zip");
             if (mCachedFile.exists() && !mCachedFile.delete()) {
+                Log.e(Logger.TAG, "FlashZip: Error while deleting already existing file");
                 throw new IOException();
             }
-                OutputStream outputStream = new FileOutputStream(mCachedFile);
+            try (
+                    InputStream in = mContext.getContentResolver().openInputStream(mUri);
+                    OutputStream outputStream = new FileOutputStream(mCachedFile)
+            ) {
                 byte buffer[] = new byte[1024];
                 int length;
                 while ((length = in.read(buffer)) > 0) {
                     outputStream.write(buffer, 0, length);
                 }
-                outputStream.close();
                 Logger.dev("FlashZip: File created successfully - " + mCachedFile.getPath());
-                in.close();
             } catch (FileNotFoundException e) {
                 Log.e(Logger.TAG, "FlashZip: Invalid Uri");
                 throw e;

app/src/main/java/com/topjohnwu/magisk/utils/ZipUtils.java

@@ -125,17 +125,16 @@ public class ZipUtils {
     }
 
     public static void unzip(File file, File folder, String path) {
-        try {
         int count;
         FileOutputStream out;
         File dest;
         InputStream is;
         JarEntry entry;
         byte data[] = new byte[4096];
-            JarFile zipfile = new JarFile(file);
+        try (JarFile zipfile = new JarFile(file)) {
-            Enumeration e = zipfile.entries();
+            Enumeration<JarEntry> e = zipfile.entries();
             while(e.hasMoreElements()) {
-                entry = (JarEntry) e.nextElement();
+                entry = e.nextElement();
                 if (!entry.getName().contains(path)
                         || entry.getName().charAt(entry.getName().length() - 1) == '/') {
                     // Ignore directories, only create files
@@ -518,10 +517,11 @@ public class ZipUtils {
                         .build(signer, publicKey));
         gen.addCertificates(certs);
         CMSSignedData sigData = gen.generate(data, false);
-        ASN1InputStream asn1 = new ASN1InputStream(sigData.getEncoded());
+        try (ASN1InputStream asn1 = new ASN1InputStream(sigData.getEncoded())) {
             DEROutputStream dos = new DEROutputStream(out);
             dos.writeObject(asn1.readObject());
         }
+    }
     /**
      * Copy all the files in a manifest from input to output.  We set
      * the modification times in the output to a fixed time, so as to