diff --git a/src/main/java/de/deadlocker8/budgetmaster/Main.java b/src/main/java/de/deadlocker8/budgetmaster/Main.java
index 5ec244a513a6320601aa32871a5e59e2f2368caf..4a059ba5a29c430935086711ec34e511abd1e008 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/Main.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/Main.java
@@ -33,6 +33,7 @@ public class Main extends SpringBootServletInitializer implements ApplicationRun
 		prepare(new String[0]);
 	}
 
+	@SuppressWarnings("ConstantConditions")
 	private static Path prepare(String[] args)
 	{
 		Localization.setDelegate(new Localization.LocalizationDelegate()
diff --git a/src/main/java/de/deadlocker8/budgetmaster/authentication/WebSecurityConfig.java b/src/main/java/de/deadlocker8/budgetmaster/authentication/WebSecurityConfig.java
index a253242be542088a621d40bf32c44fce02a9aa82..c9f9862b257d9129f1dc0dbdd6c4e6d2ded9eac4 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/authentication/WebSecurityConfig.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/authentication/WebSecurityConfig.java
@@ -8,17 +8,10 @@ import org.springframework.security.config.annotation.method.configuration.Enabl
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
 import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
-import org.springframework.security.core.Authentication;
 import org.springframework.security.core.userdetails.UserDetailsService;
 import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
 import org.springframework.security.web.DefaultRedirectStrategy;
 import org.springframework.security.web.RedirectStrategy;
-import org.springframework.security.web.authentication.AuthenticationSuccessHandler;
-
-import javax.servlet.ServletException;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-import java.io.IOException;
 
 @Configuration
 @EnableWebSecurity
diff --git a/src/main/java/de/deadlocker8/budgetmaster/database/DatabaseService.java b/src/main/java/de/deadlocker8/budgetmaster/database/DatabaseService.java
index a9d11fcb1d03dedab84be6858356b58a5f61809c..b839c70bce6a200a36cd1370ad35d0f1bad3fe3e 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/database/DatabaseService.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/database/DatabaseService.java
@@ -90,12 +90,7 @@ public class DatabaseService
 		Database database = new Database(categories, accounts, filteredTransactions);
 		LOGGER.debug("Created database JSON with " + database.getTransactions().size() + " transactions, " + database.getCategories().size() + " categories and " + database.getAccounts().size() + " accounts");
 
-		Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().setPrettyPrinting().registerTypeAdapter(DateTime.class, new JsonSerializer<DateTime>(){
-			@Override
-			public JsonElement serialize(DateTime json, Type typeOfSrc, JsonSerializationContext context) {
-				return new JsonPrimitive(ISODateTimeFormat.date().print(json));
-			}
-		}).create();
+		Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().setPrettyPrinting().registerTypeAdapter(DateTime.class, (JsonSerializer<DateTime>) (json, typeOfSrc, context) -> new JsonPrimitive(ISODateTimeFormat.date().print(json))).create();
 		return gson.toJson(database);
 	}
 
diff --git a/src/main/java/de/deadlocker8/budgetmaster/repeating/endoption/RepeatingEnd.java b/src/main/java/de/deadlocker8/budgetmaster/repeating/endoption/RepeatingEnd.java
index d7b3e4bf9063dc8c96a2b5ddb56a2e4864267c86..71a3e176a67994c0bc14d7195004a9a2dcdf9bbb 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/repeating/endoption/RepeatingEnd.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/repeating/endoption/RepeatingEnd.java
@@ -2,7 +2,6 @@ package de.deadlocker8.budgetmaster.repeating.endoption;
 
 import com.google.gson.annotations.Expose;
 import org.joda.time.DateTime;
-import org.joda.time.format.DateTimeFormat;
 
 import javax.persistence.*;
 import java.util.List;
diff --git a/src/main/java/de/deadlocker8/budgetmaster/reports/ColumnType.java b/src/main/java/de/deadlocker8/budgetmaster/reports/ColumnType.java
index afb9a7c4b6e3b48fc9b2e3875163b415647620ce..f006336f25eb0cdbf23e6cabdf1ab6c03f3927ff 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/reports/ColumnType.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/reports/ColumnType.java
@@ -20,7 +20,7 @@ public enum ColumnType
 	private String name;
 	private float proportion;
 
-	private ColumnType(String name, float proportion)
+	ColumnType(String name, float proportion)
 	{
 		this.name = name;
 		this.proportion = proportion;
diff --git a/src/main/java/de/deadlocker8/budgetmaster/reports/ReportGeneratorService.java b/src/main/java/de/deadlocker8/budgetmaster/reports/ReportGeneratorService.java
index 41faab5b82a1b405b56ba241e5dcc992a5a1db3b..13423df74e03c87b98689e1b19102a3d2a374935 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/reports/ReportGeneratorService.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/reports/ReportGeneratorService.java
@@ -45,6 +45,7 @@ public class ReportGeneratorService
 		return chapter;
 	}
 
+	@SuppressWarnings({"SameParameterValue", "ConstantConditions"})
 	private PdfPTable generateTable(ReportConfiguration reportConfiguration, int tableWidth, AmountType amountType)
 	{
 		List<ReportColumn> columns = reportConfiguration.getReportSettings().getColumnsSortedAndFiltered();
@@ -278,6 +279,7 @@ public class ReportGeneratorService
 		}
 	}
 
+	@SuppressWarnings("SameParameterValue")
 	private BaseColor getBaseColor(Color color)
 	{
 		return new BaseColor((float) color.getRed(), (float) color.getGreen(), (float) color.getBlue());
diff --git a/src/main/java/de/deadlocker8/budgetmaster/services/HelpersService.java b/src/main/java/de/deadlocker8/budgetmaster/services/HelpersService.java
index 0de8b50839cebd7cadc9461a4b6060c0fd78740f..dbb32dd306bd7d1bfeddc14d7d0b4e4ca58304da 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/services/HelpersService.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/services/HelpersService.java
@@ -161,12 +161,7 @@ public class HelpersService
 		return years;
 	}
 
-	/**
-	 * Replaces line breaks and tabs with spaces
-	 *
-	 * @param text
-	 * @return String
-	 */
+	 // Replaces line breaks and tabs with spaces
 	public String getFlatText(String text)
 	{
 		text = text.replace("\n", " ");
diff --git a/src/main/java/de/deadlocker8/budgetmaster/services/ImportService.java b/src/main/java/de/deadlocker8/budgetmaster/services/ImportService.java
index 59700cc2d22436a3c9a05036b0a54a9d7a11f29d..3dff05d49405e76715321d46617d74fb798d3b9d 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/services/ImportService.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/services/ImportService.java
@@ -60,7 +60,7 @@ public class ImportService
 				existingCategory = categoryRepository.findByNameAndColorAndType(category.getName(), category.getColor(), category.getType());
 			}
 
-			int newCategoryID = -1;
+			int newCategoryID;
 			if(existingCategory == null)
 			{
 				//category does not exist --> create it
diff --git a/src/main/java/de/deadlocker8/budgetmaster/transactions/TransactionController.java b/src/main/java/de/deadlocker8/budgetmaster/transactions/TransactionController.java
index 5510bbee6c4848bf9b1d5c42ec4a8a4250fa7523..dd1ba553a9013bd737e680281e66e474e2b17f4e 100644
--- a/src/main/java/de/deadlocker8/budgetmaster/transactions/TransactionController.java
+++ b/src/main/java/de/deadlocker8/budgetmaster/transactions/TransactionController.java
@@ -134,6 +134,7 @@ public class TransactionController extends BaseController
 		return "transactions/newTransaction";
 	}
 
+	@SuppressWarnings("ConstantConditions")
 	@RequestMapping(value = "/transactions/newTransaction", method = RequestMethod.POST)
 	public String post(Model model, @CookieValue("currentDate") String cookieDate,
 					   @ModelAttribute("NewTransaction") Transaction transaction, BindingResult bindingResult,
@@ -176,6 +177,7 @@ public class TransactionController extends BaseController
 			transaction.setTags(new ArrayList<>());
 			for(Tag currentTag : tags)
 			{
+				//noinspection ConstantConditions
 				transaction = addTagForTransaction(currentTag.getName(), transaction);
 			}
 		}
diff --git a/src/main/resources/templates/error/403.ftl b/src/main/resources/templates/error/403.ftl
index 16b4bc82f65694e8bb0be211482e56ff0f1f217d..739ecdb6ba2d1bcb9236bbaafcb0c9e30255bc89 100644
--- a/src/main/resources/templates/error/403.ftl
+++ b/src/main/resources/templates/error/403.ftl
@@ -11,9 +11,9 @@
                 <div class="col l4 offset-l4 m6 offset-m3 s10 offset-s1">
                     <div class="card background-color">
                         <div class="card-content">
-                            <span class="card-title">
+                            <div class="card-title">
                                 <div id="logo-container" class="center-align"><@header.logo "logo" ""/></div>
-                            </span>
+                            </div>
                             <div class="row">
                                 <div class="col s12 center-align">
                                     <h1>🔒 403</h1>
diff --git a/src/main/resources/templates/error/404.ftl b/src/main/resources/templates/error/404.ftl
index ac3f84a12d3eb67ca00a1e9295ef09001e224478..731c809d1dcb14d19f18fd8a6deffbda8e8129d1 100644
--- a/src/main/resources/templates/error/404.ftl
+++ b/src/main/resources/templates/error/404.ftl
@@ -11,9 +11,9 @@
                 <div class="col l4 offset-l4 m6 offset-m3 s10 offset-s1">
                     <div class="card background-color">
                         <div class="card-content">
-                            <span class="card-title">
+                            <div class="card-title">
                                 <div id="logo-container" class="center-align"><@header.logo "logo" ""/></div>
-                            </span>
+                            </div>
                             <div class="row">
                                 <div class="col s12 center-align">
                                     <h1>😔 404</h1>
diff --git a/src/main/resources/templates/error/418.ftl b/src/main/resources/templates/error/418.ftl
index df734f8f132ea6156fd24174ed7b6ab439946134..d6ec27ea5eb6b3f070c7a9ba5a5b0e41bb7dd847 100644
--- a/src/main/resources/templates/error/418.ftl
+++ b/src/main/resources/templates/error/418.ftl
@@ -11,9 +11,9 @@
                 <div class="col l4 offset-l4 m6 offset-m3 s10 offset-s1">
                     <div class="card background-color">
                         <div class="card-content">
-                            <span class="card-title">
+                            <div class="card-title">
                                 <div id="logo-container" class="center-align"><@header.logo "logo" ""/></div>
-                            </span>
+                            </div>
                             <div class="row">
                                 <div class="col s12 center-align">
                                     <img id="teapot" src="<@s.url '/images/teapot.png'/>">
diff --git a/src/main/resources/templates/error/500.ftl b/src/main/resources/templates/error/500.ftl
index 41b417ad70c038071efffbb0da36f29f90549f90..947f711739b21f7349d629ae0c53e2689dd3f87e 100644
--- a/src/main/resources/templates/error/500.ftl
+++ b/src/main/resources/templates/error/500.ftl
@@ -11,9 +11,9 @@
                 <div class="col l4 offset-l4 m6 offset-m3 s10 offset-s1">
                     <div class="card background-color">
                         <div class="card-content">
-                            <span class="card-title">
+                            <div class="card-title">
                                 <div id="logo-container" class="center-align"><@header.logo "logo" ""/></div>
-                            </span>
+                            </div>
                             <div class="row">
                                 <div class="col s12 center-align">
                                     <h1>😔 500</h1>
diff --git a/src/main/resources/templates/login.ftl b/src/main/resources/templates/login.ftl
index d6bda0528c1aa15412809da9c24128e194bb4f14..ba0be4d7621958a50d5a4994f01f232575c7b4ba 100644
--- a/src/main/resources/templates/login.ftl
+++ b/src/main/resources/templates/login.ftl
@@ -11,9 +11,9 @@
                 <div class="col l4 offset-l4 m6 offset-m3 s10 offset-s1">
                     <div class="card" id="card-login">
                         <div class="card-content">
-                            <span class="card-title">
+                            <div class="card-title">
                                 <div id="logo-container" class="center-align"><@header.logo "logo" ""/></div>
-                            </span>
+                            </div>
                             <form action="<@s.url '/login'/>" method="post">
                                 <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/>
                                 <input type="hidden" name="username" value="Default">