diff --git a/src/main/java/com/bunq/sdk/http/ApiClient.java b/src/main/java/com/bunq/sdk/http/ApiClient.java
index e747d84a..7ed201b9 100644
--- a/src/main/java/com/bunq/sdk/http/ApiClient.java
+++ b/src/main/java/com/bunq/sdk/http/ApiClient.java
@@ -238,7 +238,7 @@ private void setDefaultHeaders(BunqRequestBuilder httpEntity) {
     BunqHeader.userAgent.addTo(httpEntity);
     BunqHeader.language.addTo(httpEntity);
     BunqHeader.region.addTo(httpEntity);
-    BunqHeader.clientRequestId.addTo(httpEntity,UUID.randomUUID().toString());
+    BunqHeader.clientRequestId.addTo(httpEntity, UUID.randomUUID().toString());
     BunqHeader.geolocation.addTo(httpEntity);
   }
 
@@ -256,8 +256,8 @@ private void setSessionHeaders(BunqRequestBuilder requestBuilder) {
     String sessionToken = apiContext.getSessionToken();
 
     if (sessionToken != null) {
-      BunqHeader.clientAuthentication.addTo(requestBuilder,sessionToken);
-      BunqHeader.clientSignature.addTo(requestBuilder,generateSignature(requestBuilder));
+      BunqHeader.clientAuthentication.addTo(requestBuilder, sessionToken);
+      BunqHeader.clientSignature.addTo(requestBuilder, generateSignature(requestBuilder));
     }
   }
 
diff --git a/src/main/java/com/bunq/sdk/http/BunqBasicHeader.java b/src/main/java/com/bunq/sdk/http/BunqBasicHeader.java
index a73dd2ec..b2672c7c 100644
--- a/src/main/java/com/bunq/sdk/http/BunqBasicHeader.java
+++ b/src/main/java/com/bunq/sdk/http/BunqBasicHeader.java
@@ -17,7 +17,7 @@ public class BunqBasicHeader {
   private final BunqHeader name;
   private final String value;
 
-  public static BunqBasicHeader get(BunqHeader header,Response response) {
+  public static BunqBasicHeader get(BunqHeader header, Response response) {
     return new BunqBasicHeader(header, response.header(header.getHeader()));
   }
 
@@ -35,7 +35,7 @@ public String getValue() {
   }
 
   private String forSigning() {
-    return getName().getHeader()+DELIMITER_HEADER_NAME_AND_VALUE+getValue();
+    return getName().getHeader() + DELIMITER_HEADER_NAME_AND_VALUE + getValue();
   }
 
   public static String collectForSigning(
@@ -67,4 +67,4 @@ public static String collectForSigning(
 
     return stringBuffer.toString();
   }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/com/bunq/sdk/http/BunqHeader.java b/src/main/java/com/bunq/sdk/http/BunqHeader.java
index 5ab93ecc..519df850 100644
--- a/src/main/java/com/bunq/sdk/http/BunqHeader.java
+++ b/src/main/java/com/bunq/sdk/http/BunqHeader.java
@@ -5,7 +5,7 @@
 
 public enum BunqHeader {
     attachmentDescription("X-Bunq-Attachment-Description"),
-    cacheControl("Cache-Control","no-cache"),
+    cacheControl("Cache-Control", "no-cache"),
     contentType("Content-Type"),
     clientAuthentication("X-Bunq-Client-Authentication"),
     clientEncryptionHMAC("X-Bunq-Client-Encryption-Hmac"),
@@ -26,7 +26,7 @@ public enum BunqHeader {
     private final String defaultValue;
 
     BunqHeader(String header) {
-        this(header,null);
+        this(header, null);
     }
 
     BunqHeader(String header, String defaultValue) {
@@ -53,15 +53,19 @@ public String getDefaultValue() {
     }
 
     private String getOrDefault(String value) {
-        return value != null ? value : getDefaultValue();
+        if (value != null) {
+            return value;
+        }
+
+        return getDefaultValue();
     }
 
-    public void addTo(Map<String,String> headers, String value) {
+    public void addTo(Map<String, String> headers, String value) {
         headers.put(getHeader(), getOrDefault(value));
     }
 
     public void addTo(BunqRequestBuilder requestBuilder) {
-        addTo(requestBuilder,null);
+        addTo(requestBuilder, null);
     }
 
     public void addTo(BunqRequestBuilder requestBuilder, String value) {
@@ -86,7 +90,7 @@ private String findKey(Collection<String> keys) {
         return null;
     }
 
-    public String getOrDefault(Map<String,String> headers) {
+    public String getOrDefault(Map<String, String> headers) {
         String key = findKey(headers.keySet());
         if (key != null && headers.get(key) != null) {
             return headers.get(key);
diff --git a/src/main/java/com/bunq/sdk/http/BunqRequestBuilder.java b/src/main/java/com/bunq/sdk/http/BunqRequestBuilder.java
index d89ed3cb..a52dd82c 100644
--- a/src/main/java/com/bunq/sdk/http/BunqRequestBuilder.java
+++ b/src/main/java/com/bunq/sdk/http/BunqRequestBuilder.java
@@ -75,7 +75,7 @@ public BunqRequestBuilder url(URL url) {
     return (BunqRequestBuilder) super.url(url);
   }
 
-  private void addToAllHeader(String name,String value) {
+  private void addToAllHeader(String name, String value) {
     BunqHeader header = BunqHeader.parse(name);
 
     if (header != null) {
diff --git a/src/main/java/com/bunq/sdk/security/SecurityUtils.java b/src/main/java/com/bunq/sdk/security/SecurityUtils.java
index a45a0bf2..484ce31d 100644
--- a/src/main/java/com/bunq/sdk/security/SecurityUtils.java
+++ b/src/main/java/com/bunq/sdk/security/SecurityUtils.java
@@ -3,7 +3,10 @@
 import com.bunq.sdk.context.ApiContext;
 import com.bunq.sdk.exception.BunqException;
 import com.bunq.sdk.exception.UncaughtExceptionError;
-import com.bunq.sdk.http.*;
+import com.bunq.sdk.http.BunqBasicHeader;
+import com.bunq.sdk.http.BunqHeader;
+import com.bunq.sdk.http.BunqRequestBuilder;
+import com.bunq.sdk.http.HttpMethod;
 import okhttp3.Headers;
 import okhttp3.Response;
 import okio.BufferedSink;
@@ -30,7 +33,12 @@
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.PKCS8EncodedKeySpec;
 import java.security.spec.X509EncodedKeySpec;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Base64;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 
 /**
  * Static lib containing methods for handling encryption.
@@ -383,7 +391,7 @@ private static String generateRequestHeadersSortedString(BunqRequestBuilder bunq
     return BunqBasicHeader.collectForSigning(
             bunqRequestBuilder.getAllHeader(),
             null,
-            Arrays.asList(BunqHeader.cacheControl,BunqHeader.userAgent)
+            Arrays.asList(BunqHeader.cacheControl, BunqHeader.userAgent)
     );
   }
 
@@ -459,7 +467,7 @@ public static void validateResponseSignature(
         response.headers()
     );
     Signature signature = getSignatureInstance();
-    BunqBasicHeader serverSignature = BunqBasicHeader.get(BunqHeader.serverSignature,response);
+    BunqBasicHeader serverSignature = BunqBasicHeader.get(BunqHeader.serverSignature, response);
 
     byte[] serverSignatureBase64Bytes = serverSignature.getValue().getBytes();
     byte[] serverSignatureDecoded = Base64.getDecoder().decode(serverSignatureBase64Bytes);
@@ -478,12 +486,12 @@ private static byte[] getResponseBytes(
       BunqHeader header = BunqHeader.parse(allHeader.name(i));
 
       if (header != null && !BunqHeader.serverSignature.equals(header)) {
-        allResponseHeader.add(new BunqBasicHeader(header,allHeader.get(allHeader.name(i))));
+        allResponseHeader.add(new BunqBasicHeader(header, allHeader.get(allHeader.name(i))));
       }
     }
 
     try {
-      outputStream.write(getResponseHeadBytes(responseCode,allResponseHeader));
+      outputStream.write(getResponseHeadBytes(responseCode, allResponseHeader));
       outputStream.write(responseBodyBytes);
     } catch (IOException exception) {
       throw new UncaughtExceptionError(exception);
@@ -492,9 +500,9 @@ private static byte[] getResponseBytes(
     return outputStream.toByteArray();
   }
 
-  private static byte[] getResponseHeadBytes(int responseCode, List<BunqBasicHeader> responseHeaders) {
-    String requestHeadString = responseCode + NEWLINE +
-        generateResponseHeadersSortedString(responseHeaders) + NEWLINE + NEWLINE;
+  private static byte[] getResponseHeadBytes(int code, List<BunqBasicHeader> headers) {
+    String requestHeadString = code + NEWLINE +
+        generateResponseHeadersSortedString(headers) + NEWLINE + NEWLINE;
 
     return requestHeadString.getBytes();
   }
diff --git a/src/test/java/com/bunq/sdk/http/BunqHeaderTest.java b/src/test/java/com/bunq/sdk/http/BunqHeaderTest.java
index 748fa413..ddaf0c78 100644
--- a/src/test/java/com/bunq/sdk/http/BunqHeaderTest.java
+++ b/src/test/java/com/bunq/sdk/http/BunqHeaderTest.java
@@ -1,10 +1,14 @@
 package com.bunq.sdk.http;
 
-import org.junit.Test;
+import java.util.Collections;
+import java.util.Map;
+import java.util.HashMap;
 
-import java.util.*;
+import org.junit.Test;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 public class BunqHeaderTest {
     @Test
@@ -40,9 +44,12 @@ public void isBunq() {
     public void getOrDefault() {
         BunqHeader h = BunqHeader.clientResponseId;
 
-        assertEquals("test-id", h.getOrDefault(Collections.singletonMap("x-bunq-client-response-id", "test-id")));
-        assertEquals("Could not determine response id.", h.getOrDefault(Collections.singletonMap("x-bunq-some-other-header", "test-id")));
-        assertEquals("Could not determine response id.", h.getOrDefault(Collections.<String,String>emptyMap()));
+        assertEquals("test-id",
+                h.getOrDefault(Collections.singletonMap("x-bunq-client-response-id", "test-id")));
+        assertEquals("Could not determine response id.",
+                h.getOrDefault(Collections.singletonMap("x-bunq-some-other-header", "test-id")));
+        assertEquals("Could not determine response id.",
+                h.getOrDefault(Collections.<String, String>emptyMap()));
     }
 
     @Test