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/preference/LogExporterPreference.java

@@ -75,7 +75,8 @@ public class LogExporterPreference extends Preference {
                         throw new Exception(errors.toString());
                     }
                 }
-            } catch (Exception e) {
+            } catch (final Exception e) {
+                // noinspection ResultOfMethodCallIgnored
                 file.delete();
                 throw e;
             }

app/src/main/java/com/wireguard/android/preference/VersionPreference.java

@@ -27,10 +27,9 @@ public class VersionPreference extends Preference {
             versionSummary = getContext().getString(R.string.version_userspace_summary, GoBackend.getVersion());
         } else if (Application.getComponent().getBackendType() == WgQuickBackend.class) {
             Application.getComponent().getToolsInstaller().getVersion().whenComplete((version, exception) -> {
-                if (exception == null)
-                    versionSummary = getContext().getString(R.string.version_kernel_summary, version);
-                else
-                    versionSummary = getContext().getString(R.string.version_kernel_unknown_summary);
+                versionSummary = exception == null
+                        ? getContext().getString(R.string.version_kernel_summary, version)
+                        : getContext().getString(R.string.version_kernel_unknown_summary);
                 notifyChanged();
             });
         }

app/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java

@@ -81,8 +81,7 @@ public class ZipExporterPreference extends Preference {
                                     toString().getBytes(StandardCharsets.UTF_8));
                         }
                         zip.closeEntry();
-                        zip.close();
-                    } catch (Exception e) {
+                    } catch (final Exception e) {
                         // noinspection ResultOfMethodCallIgnored
                         file.delete();
                         throw e;