Don't try to catch exceptions that'll never be thrown

.idea/misc.xml

@@ -24,7 +24,7 @@
       </value>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="JDK" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">

app/src/main/java/me/impy/aegis/crypto/CryptoUtils.java

@@ -39,8 +39,7 @@ public class CryptoUtils {
     public static final int CRYPTO_SCRYPT_r = 8;
     public static final int CRYPTO_SCRYPT_p = 1;
 
-    public static SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p)
-            throws NoSuchAlgorithmException, InvalidKeySpecException {
+    public static SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p) {
         byte[] bytes = toBytes(password);
         byte[] keyBytes = SCrypt.generate(bytes, salt, n, r, p, CRYPTO_KEY_SIZE);
         return new SecretKeySpec(keyBytes, 0, keyBytes.length, "AES");

app/src/main/java/me/impy/aegis/db/slots/PasswordSlot.java

@@ -49,25 +49,17 @@ public class PasswordSlot extends RawSlot {
         }
     }
 
-    public SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p) throws SlotException {
-        try {
-            SecretKey key = CryptoUtils.deriveKey(password, salt, n, r, p);
-            _n = n;
-            _r = r;
-            _p = p;
-            _salt = salt;
-            return key;
-        } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
-            throw new SlotException(e);
-        }
+    public SecretKey deriveKey(char[] password, byte[] salt, int n, int r, int p) {
+        SecretKey key = CryptoUtils.deriveKey(password, salt, n, r, p);
+        _n = n;
+        _r = r;
+        _p = p;
+        _salt = salt;
+        return key;
     }
 
-    public SecretKey deriveKey(char[] password) throws SlotException {
-        try {
-            return CryptoUtils.deriveKey(password, _salt, _n, _r, _p);
-        } catch (InvalidKeySpecException | NoSuchAlgorithmException e) {
-            throw new SlotException(e);
-        }
+    public SecretKey deriveKey(char[] password) {
+        return CryptoUtils.deriveKey(password, _salt, _n, _r, _p);
     }
 
     @Override

app/src/main/java/me/impy/aegis/ui/PreferencesActivity.java

@@ -26,7 +26,7 @@ public class PreferencesActivity extends AegisActivity implements PasswordDialog
     }
 
     @Override
-    protected final void onRestoreInstanceState(final Bundle inState) {
+    protected void onRestoreInstanceState(final Bundle inState) {
         // pass the stored result intent back to the fragment
         if (inState.containsKey("result")) {
             _fragment.setResult(inState.getParcelable("result"));
@@ -35,7 +35,7 @@ public class PreferencesActivity extends AegisActivity implements PasswordDialog
     }
 
     @Override
-    protected final void onSaveInstanceState(final Bundle outState) {
+    protected void onSaveInstanceState(final Bundle outState) {
         // save the result intent of the fragment
         // this is done so we don't lose anything if the fragment calls recreate on this activity
         outState.putParcelable("result", _fragment.getResult());

app/src/main/java/me/impy/aegis/ui/tasks/DerivationTask.java

@@ -21,12 +21,8 @@ public class DerivationTask extends ProgressDialogTask<DerivationTask.Params, Se
         setPriority();
 
         Params params = args[0];
-        try {
-            byte[] salt = CryptoUtils.generateSalt();
-            return params.Slot.deriveKey(params.Password, salt, CryptoUtils.CRYPTO_SCRYPT_N, CryptoUtils.CRYPTO_SCRYPT_r, CryptoUtils.CRYPTO_SCRYPT_p);
-        } catch (SlotException e) {
-            return null;
-        }
+        byte[] salt = CryptoUtils.generateSalt();
+        return params.Slot.deriveKey(params.Password, salt, CryptoUtils.CRYPTO_SCRYPT_N, CryptoUtils.CRYPTO_SCRYPT_r, CryptoUtils.CRYPTO_SCRYPT_p);
     }
 
     @Override