diff --git a/src/main/java/eu/hbp/mip/configurations/KeycloakConfiguration.java b/src/main/java/eu/hbp/mip/configurations/KeycloakConfiguration.java
index 390b1d6532eefdcc95b6baf9df0f5a90f3e00515..e3097df3bc5d9f65ba4b0d3937588fb92d462518 100644
--- a/src/main/java/eu/hbp/mip/configurations/KeycloakConfiguration.java
+++ b/src/main/java/eu/hbp/mip/configurations/KeycloakConfiguration.java
@@ -10,4 +10,4 @@ public class KeycloakConfiguration {
     public KeycloakSpringBootConfigResolver KeycloakConfigResolver() {
         return new KeycloakSpringBootConfigResolver();
     }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/eu/hbp/mip/configurations/SecurityConfiguration.java b/src/main/java/eu/hbp/mip/configurations/SecurityConfiguration.java
index f86270f4532fc440151ee50b9101754f79486de6..c7c30ab55ce60a58f1da79e358ffbc0637f6ec45 100644
--- a/src/main/java/eu/hbp/mip/configurations/SecurityConfiguration.java
+++ b/src/main/java/eu/hbp/mip/configurations/SecurityConfiguration.java
@@ -1,6 +1,7 @@
 package eu.hbp.mip.configurations;
 
 import eu.hbp.mip.utils.CORSFilter;
+import org.jetbrains.annotations.NotNull;
 import org.keycloak.adapters.springsecurity.KeycloakConfiguration;
 import org.keycloak.adapters.springsecurity.authentication.KeycloakAuthenticationProvider;
 import org.keycloak.adapters.springsecurity.config.KeycloakWebSecurityConfigurerAdapter;
@@ -69,8 +70,8 @@ public class SecurityConfiguration extends KeycloakWebSecurityConfigurerAdapter
     private Filter csrfHeaderFilter() {
         return new OncePerRequestFilter() {
             @Override
-            protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
-                                            FilterChain filterChain) throws ServletException, IOException {
+            protected void doFilterInternal(@NotNull HttpServletRequest request, @NotNull HttpServletResponse response,
+                                            @NotNull FilterChain filterChain) throws ServletException, IOException {
                 CsrfToken csrf = (CsrfToken) request.getAttribute(CsrfToken.class.getName());
                 if (csrf != null) {
                     Cookie cookie = WebUtils.getCookie(request, "XSRF-TOKEN");
diff --git a/src/main/java/eu/hbp/mip/repositories/ExperimentSpecifications.java b/src/main/java/eu/hbp/mip/repositories/ExperimentSpecifications.java
index 3379610d5612be715efa4e121fa94faf375acb5c..08423757f2c937a2c0f823063e675726dc2335d0 100644
--- a/src/main/java/eu/hbp/mip/repositories/ExperimentSpecifications.java
+++ b/src/main/java/eu/hbp/mip/repositories/ExperimentSpecifications.java
@@ -12,7 +12,7 @@ import java.util.List;
 public class ExperimentSpecifications {
     public static class ExperimentWithName implements Specification<ExperimentDAO> {
 
-        private String name;
+        private final String name;
         private String regExp;
 
         public ExperimentWithName(String name) {
@@ -33,7 +33,7 @@ public class ExperimentSpecifications {
 
     public static class ExperimentWithAlgorithm implements Specification<ExperimentDAO> {
 
-        private String algorithm;
+        private final String algorithm;
 
         public ExperimentWithAlgorithm(String algorithm) {
             this.algorithm = algorithm;
@@ -50,7 +50,7 @@ public class ExperimentSpecifications {
 
     public static class ExperimentWithViewed implements Specification<ExperimentDAO> {
 
-        private Boolean viewed;
+        private final Boolean viewed;
 
         public ExperimentWithViewed(Boolean viewed) {
             this.viewed = viewed;
@@ -66,7 +66,7 @@ public class ExperimentSpecifications {
 
     public static class ExperimentWithShared implements Specification<ExperimentDAO> {
 
-        private Boolean shared;
+        private final Boolean shared;
 
         public ExperimentWithShared(Boolean shared) {
             this.shared = shared;
@@ -82,7 +82,7 @@ public class ExperimentSpecifications {
 
     public static class MyExperiment implements Specification<ExperimentDAO> {
 
-        private String username;
+        private final String username;
 
         public MyExperiment(String username) {
             this.username = username;
@@ -99,14 +99,14 @@ public class ExperimentSpecifications {
 
     public static class SharedExperiment implements Specification<ExperimentDAO> {
 
-        private boolean shared;
+        private final boolean shared;
 
         public SharedExperiment(boolean shared) {
             this.shared = shared;
         }
 
         public Predicate toPredicate(Root<ExperimentDAO> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder cb) {
-            if (shared == false) {
+            if (!shared) {
                 return cb.isTrue(cb.literal(false));
             }
             return cb.equal(root.get("shared"), shared);
@@ -115,8 +115,8 @@ public class ExperimentSpecifications {
 
     public static class ExperimentOrderBy implements Specification<ExperimentDAO> {
 
-        private String orderBy;
-        private Boolean descending;
+        private final String orderBy;
+        private final Boolean descending;
 
         public ExperimentOrderBy(String orderBy, Boolean descending) {
             if (properColumnToBeOrderedBy(orderBy))
diff --git a/src/main/java/eu/hbp/mip/services/GalaxyService.java b/src/main/java/eu/hbp/mip/services/GalaxyService.java
index 61d5629fdc0e5ce52845638be65f71b8608574a2..23c15d710a1a5c3725080f977e28b0a54b3be00c 100644
--- a/src/main/java/eu/hbp/mip/services/GalaxyService.java
+++ b/src/main/java/eu/hbp/mip/services/GalaxyService.java
@@ -173,7 +173,7 @@ public class GalaxyService {
             Response<Object> response = call.execute();
             if (response.code() >= 400) {
                 Logger.LogBackgroundAction(experimentName, experimentId, " Response code: "
-                        + response.code() + "" + " with body: " + (response.errorBody() != null ? response.errorBody().string() : " "));
+                        + response.code() + " with body: " + (response.errorBody() != null ? response.errorBody().string() : " "));
                 return "internalError";
             }
             result = new Gson().toJson(response.body());
@@ -228,7 +228,7 @@ public class GalaxyService {
             Response<List<GalaxyWorkflowResult>> response = call.execute();
             if (response.code() >= 400) {
                 Logger.LogBackgroundAction(experimentName, experimentId, " Response code: "
-                        + response.code() + "" + " with body: " + (response.errorBody() != null ? response.errorBody().string() : " "));
+                        + response.code() + " with body: " + (response.errorBody() != null ? response.errorBody().string() : " "));
                 return null;
             }
             getGalaxyWorkflowResultList = response.body();
@@ -266,7 +266,7 @@ public class GalaxyService {
             Response<Object> response = call.execute();
             if (response.code() >= 400) {
                 Logger.LogBackgroundAction(experimentName, experimentId, " Response code: "
-                        + response.code() + "" + " with body: " + (response.errorBody() != null ? response.errorBody().string() : " "));
+                        + response.code() + " with body: " + (response.errorBody() != null ? response.errorBody().string() : " "));
                 return null;
             }
             resultJson = new Gson().toJson(response.body());
diff --git a/src/main/java/eu/hbp/mip/utils/ErrorMessage.java b/src/main/java/eu/hbp/mip/utils/ErrorMessage.java
index ef15c71ae041b277e51c487afb03d17d11556aa8..fdaac15921a846f710f89398a799c41e7a6befa8 100644
--- a/src/main/java/eu/hbp/mip/utils/ErrorMessage.java
+++ b/src/main/java/eu/hbp/mip/utils/ErrorMessage.java
@@ -4,10 +4,10 @@ package eu.hbp.mip.utils;
 import java.util.Date;
 
 public class ErrorMessage {
-    private int statusCode;
-    private Date timestamp;
-    private String message;
-    private String description;
+    private final int statusCode;
+    private final Date timestamp;
+    private final String message;
+    private final String description;
 
     public ErrorMessage(int statusCode, Date timestamp, String message, String description) {
         this.statusCode = statusCode;
diff --git a/src/main/java/eu/hbp/mip/utils/HTTPUtil.java b/src/main/java/eu/hbp/mip/utils/HTTPUtil.java
index cd3778a00b94083bf52e59234527b71f7036d594..fdd7a9179cbb95bccb73277212a2dd29b5b20b41 100644
--- a/src/main/java/eu/hbp/mip/utils/HTTPUtil.java
+++ b/src/main/java/eu/hbp/mip/utils/HTTPUtil.java
@@ -70,7 +70,7 @@ public class HTTPUtil {
             response.append(inputLine);
         }
         in.close();
-        resp.append(response.toString());
+        resp.append(response);
 
         return respCode;
     }
diff --git a/src/main/java/eu/hbp/mip/utils/Logger.java b/src/main/java/eu/hbp/mip/utils/Logger.java
index c21e2fdc9391be017fed2b470ff04e11d29a45fd..7ea51d74f008f3e5eef6760fc8693dc5d69d5240 100644
--- a/src/main/java/eu/hbp/mip/utils/Logger.java
+++ b/src/main/java/eu/hbp/mip/utils/Logger.java
@@ -8,8 +8,8 @@ import java.util.UUID;
 public class Logger {
 
     private static final org.slf4j.Logger LOGGER = LoggerFactory.getLogger(Logger.class);
-    private  String username;
-    private  String endpoint;
+    private final String username;
+    private final String endpoint;
 
     public Logger(String username, String endpoint){
         this.username = username;