diff --git a/src/main/java/fr/xephi/authme/api/API.java b/src/main/java/fr/xephi/authme/api/API.java
index 7fe3d43ed..e849e7950 100644
--- a/src/main/java/fr/xephi/authme/api/API.java
+++ b/src/main/java/fr/xephi/authme/api/API.java
@@ -157,10 +157,7 @@ public class API {
                 return false;
             }
             PlayerAuth auth = new PlayerAuth(name, hash, "198.18.0.1", 0, "your@email.com", playerName);
-            if (!instance.database.saveAuth(auth)) {
-                return false;
-            }
-            return true;
+            return instance.database.saveAuth(auth);
         } catch (NoSuchAlgorithmException ex) {
             return false;
         }
diff --git a/src/main/java/fr/xephi/authme/datasource/FlatFile.java b/src/main/java/fr/xephi/authme/datasource/FlatFile.java
index 9901a0fa3..19c93ea3a 100644
--- a/src/main/java/fr/xephi/authme/datasource/FlatFile.java
+++ b/src/main/java/fr/xephi/authme/datasource/FlatFile.java
@@ -744,9 +744,10 @@ public class FlatFile implements DataSource {
             for (String l : lines) {
                 bw.write(l + "\n");
             }
+
         } catch (IOException ex) {
             ConsoleLogger.showError(ex.getMessage());
-            return;
+
         } finally {
             if (br != null) {
                 try {
@@ -761,7 +762,6 @@ public class FlatFile implements DataSource {
                 }
             }
         }
-        return;
     }
 
     /**
diff --git a/src/main/java/fr/xephi/authme/security/crypts/CryptPBKDF2.java b/src/main/java/fr/xephi/authme/security/crypts/CryptPBKDF2.java
index c93171af1..cdf256a99 100644
--- a/src/main/java/fr/xephi/authme/security/crypts/CryptPBKDF2.java
+++ b/src/main/java/fr/xephi/authme/security/crypts/CryptPBKDF2.java
@@ -4,6 +4,7 @@ import fr.xephi.authme.security.pbkdf2.PBKDF2Engine;
 import fr.xephi.authme.security.pbkdf2.PBKDF2Parameters;
 
 import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
 
 /**
  */
@@ -25,7 +26,7 @@ public class CryptPBKDF2 implements EncryptionMethod {
         PBKDF2Parameters params = new PBKDF2Parameters("HmacSHA256", "ASCII", salt.getBytes(), 10000);
         PBKDF2Engine engine = new PBKDF2Engine(params);
 
-        return result + String.valueOf(engine.deriveKey(password, 64));
+        return result + Arrays.toString(engine.deriveKey(password, 64));
     }
 
     /**
diff --git a/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2.java b/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2.java
index c66a42ec3..d1dab3025 100644
--- a/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2.java
+++ b/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2.java
@@ -41,7 +41,7 @@ public interface PBKDF2 {
      *
      * @return internal byte array
      */
-    public abstract byte[] deriveKey(String inputPassword);
+    byte[] deriveKey(String inputPassword);
 
     /**
      * Convert String-based input to internal byte array, then invoke PBKDF2.
@@ -51,7 +51,7 @@ public interface PBKDF2 {
      *
      * @return internal byte array
      */
-    public abstract byte[] deriveKey(String inputPassword, int dkLen);
+    byte[] deriveKey(String inputPassword, int dkLen);
 
     /**
      * Convert String-based input to internal byte arrays, then invoke PBKDF2
@@ -63,28 +63,28 @@ public interface PBKDF2 {
      * @return <code>true</code> password match; <code>false</code> incorrect
      * password
      */
-    public abstract boolean verifyKey(String inputPassword);
+    boolean verifyKey(String inputPassword);
 
     /**
      * Allow reading of configured parameters.
      *
      * @return Currently set parameters.
      */
-    public abstract PBKDF2Parameters getParameters();
+    PBKDF2Parameters getParameters();
 
     /**
      * Allow setting of configured parameters.
      *
      * @param parameters
      */
-    public abstract void setParameters(PBKDF2Parameters parameters);
+    void setParameters(PBKDF2Parameters parameters);
 
     /**
      * Get currently set Pseudo Random Function.
      *
      * @return Currently set Pseudo Random Function
      */
-    public abstract PRF getPseudoRandomFunction();
+    PRF getPseudoRandomFunction();
 
     /**
      * Set the Pseudo Random Function to use. Note that deriveKeys/getPRF does
@@ -93,5 +93,5 @@ public interface PBKDF2 {
      *
      * @param prf Pseudo Random Function to set.
      */
-    public abstract void setPseudoRandomFunction(PRF prf);
+    void setPseudoRandomFunction(PRF prf);
 }
diff --git a/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2Formatter.java b/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2Formatter.java
index dc82ea208..3916d1c03 100644
--- a/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2Formatter.java
+++ b/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2Formatter.java
@@ -40,7 +40,7 @@ public interface PBKDF2Formatter {
      *
      * @return String representation
      */
-    public abstract String toString(PBKDF2Parameters p);
+    String toString(PBKDF2Parameters p);
 
     /**
      * Convert String to parameters. Depending on actual implementation, it may
@@ -52,5 +52,5 @@ public interface PBKDF2Formatter {
      * @return <code>false</code> syntax OK, <code>true</code> some syntax
      * issue.
      */
-    public abstract boolean fromString(PBKDF2Parameters p, String s);
+    boolean fromString(PBKDF2Parameters p, String s);
 }
diff --git a/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2HexFormatter.java b/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2HexFormatter.java
index ed07217ff..2309d77f1 100644
--- a/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2HexFormatter.java
+++ b/src/main/java/fr/xephi/authme/security/pbkdf2/PBKDF2HexFormatter.java
@@ -47,7 +47,7 @@ public class PBKDF2HexFormatter implements PBKDF2Formatter {
         }
 
         String[] p123 = s.split(":");
-        if (p123 == null || p123.length != 3) {
+        if (p123.length != 3) {
             return true;
         }
 
diff --git a/src/main/java/fr/xephi/authme/security/pbkdf2/PRF.java b/src/main/java/fr/xephi/authme/security/pbkdf2/PRF.java
index 408588c6d..af40e171d 100644
--- a/src/main/java/fr/xephi/authme/security/pbkdf2/PRF.java
+++ b/src/main/java/fr/xephi/authme/security/pbkdf2/PRF.java
@@ -39,7 +39,7 @@ public interface PRF {
      * @param P The password supplied as array of bytes. It is the caller's
      *          task to convert String passwords to bytes as appropriate.
      */
-    public void init(byte[] P);
+    void init(byte[] P);
 
     /**
      * Pseudo Random Function
@@ -49,12 +49,12 @@ public interface PRF {
      *
      * @return Random bytes of hLen length.
      */
-    public byte[] doFinal(byte[] M);
+    byte[] doFinal(byte[] M);
 
     /**
      * Query block size of underlying algorithm/mechanism.
      *
      * @return block size
      */
-    public int getHLen();
+    int getHLen();
 }
diff --git a/src/main/java/fr/xephi/authme/util/Utils.java b/src/main/java/fr/xephi/authme/util/Utils.java
index 1a83b570e..0ff0867f8 100644
--- a/src/main/java/fr/xephi/authme/util/Utils.java
+++ b/src/main/java/fr/xephi/authme/util/Utils.java
@@ -268,6 +268,7 @@ public final class Utils {
             if (target.isDirectory()) {
                 purgeDirectory(target);
             }
+            //noinspection ResultOfMethodCallIgnored
             target.delete();
         }
     }
diff --git a/src/test/java/fr/xephi/authme/util/UtilsTest.java b/src/test/java/fr/xephi/authme/util/UtilsTest.java
index cb1ed19ad..085e5b273 100644
--- a/src/test/java/fr/xephi/authme/util/UtilsTest.java
+++ b/src/test/java/fr/xephi/authme/util/UtilsTest.java
@@ -25,15 +25,12 @@ import static org.mockito.Mockito.when;
  */
 public class UtilsTest {
 
-    private AuthMe authMeMock;
-    private PermissionsManager permissionsManagerMock;
-
     @Before
     public void setUpMocks() {
         AuthMeMockUtil.mockAuthMeInstance();
-        authMeMock = AuthMe.getInstance();
+        AuthMe authMeMock = AuthMe.getInstance();
 
-        permissionsManagerMock = mock(PermissionsManager.class);
+        PermissionsManager permissionsManagerMock = mock(PermissionsManager.class);
         when(authMeMock.getPermissionsManager()).thenReturn(permissionsManagerMock);
 
         Server serverMock = mock(Server.class);