diff --git a/modules/time-calc-app/pom.xml b/modules/time-calc-app/pom.xml
index d70bdb1..68ae852 100644
--- a/modules/time-calc-app/pom.xml
+++ b/modules/time-calc-app/pom.xml
@@ -24,7 +24,7 @@
                 <configuration>
                     <archive>
                         <manifest>
-                            <mainClass>org.nanoboot.utils.timecalc.main.Main</mainClass>
+                            <mainClass>org.nanoboot.utils.timecalc.app.Main</mainClass>
                             <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                         </manifest>
                         <manifestEntries>
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/Main.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/Main.java
similarity index 79%
rename from modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/Main.java
rename to modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/Main.java
index ec593a6..19dd465 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/Main.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/Main.java
@@ -1,9 +1,9 @@
-package org.nanoboot.utils.timecalc.main;
+package org.nanoboot.utils.timecalc.app;
 
 import java.io.IOException;
 
 /**
- * @author pc00289
+ * @author Robert
  * @since 31.01.2024
  */
 public class Main {
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcApp.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcApp.java
similarity index 98%
rename from modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcApp.java
rename to modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcApp.java
index 89b4416..71440a8 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcApp.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcApp.java
@@ -1,4 +1,4 @@
-package org.nanoboot.utils.timecalc.main;
+package org.nanoboot.utils.timecalc.app;
 
 import org.nanoboot.utils.timecalc.utils.Constants;
 import org.nanoboot.utils.timecalc.utils.FileConstants;
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcConf.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcConf.java
similarity index 97%
rename from modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcConf.java
rename to modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcConf.java
index 7516a1b..c7ae5f1 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcConf.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcConf.java
@@ -1,4 +1,4 @@
-package org.nanoboot.utils.timecalc.main;
+package org.nanoboot.utils.timecalc.app;
 
 import java.io.File;
 import java.io.FileInputStream;
@@ -6,7 +6,7 @@ import java.io.IOException;
 import java.util.Properties;
 
 /**
- * @author pc00289
+ * @author Robert
  * @since 20.02.2024
  */
 public class TimeCalcConf {
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcException.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcException.java
similarity index 72%
rename from modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcException.java
rename to modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcException.java
index c0f4fc9..a620ff3 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcException.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcException.java
@@ -1,7 +1,7 @@
-package org.nanoboot.utils.timecalc.main;
+package org.nanoboot.utils.timecalc.app;
 
 /**
- * @author pc00289
+ * @author Robert
  * @since 21.02.2024
  */
 public class TimeCalcException extends RuntimeException{
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcManager.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcManager.java
similarity index 99%
rename from modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcManager.java
rename to modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcManager.java
index c4310c3..098d123 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/main/TimeCalcManager.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/app/TimeCalcManager.java
@@ -1,4 +1,4 @@
-package org.nanoboot.utils.timecalc.main;
+package org.nanoboot.utils.timecalc.app;
 
 import org.nanoboot.utils.timecalc.swing.common.AboutButton;
 import org.nanoboot.utils.timecalc.swing.common.ComponentRegistry;
@@ -34,7 +34,7 @@ import java.util.Calendar;
 import java.util.Date;
 
 /**
- * @author pc00289
+ * @author Robert
  * @since 08.02.2024
  */
 public class TimeCalcManager {
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/entity/Activity.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/entity/Activity.java
new file mode 100644
index 0000000..17b39d4
--- /dev/null
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/entity/Activity.java
@@ -0,0 +1,26 @@
+package org.nanoboot.utils.timecalc.entity;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+/**
+ * @author Robert
+ * @since 23.02.2024
+ */
+@Getter
+@Setter
+@ToString
+public class Activity {
+    private int year;
+    private int month;
+    private int day;
+    private int name;
+    private int comment;
+    private int ticket;
+    private int spentHours;
+    private int spentMinutes;
+    private boolean jira;
+    private boolean bugzilla;
+
+}
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/entity/WorkingDay.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/entity/WorkingDay.java
new file mode 100644
index 0000000..37f3088
--- /dev/null
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/entity/WorkingDay.java
@@ -0,0 +1,31 @@
+package org.nanoboot.utils.timecalc.entity;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+/**
+ * @author Robert
+ * @since 23.02.2024
+ */
+@Getter
+@Setter
+@ToString
+public class WorkingDay {
+    private int year;
+    private int month;
+    private int day;
+    private int arrivalHour;
+    private int arrivalMinute;
+    private int departureHour;
+    private int departureMinute;
+    private String note;
+    private int overtimeHoursThisDay;
+    private int overtimeMinutesThisDay;
+    private int compensatoryTimeOffHoursThisDay;
+    private int compensatoryTimeOffMinutesThisDay;
+    private int overtimeHoursToBeCompensatedUntilThisDay;
+    private int overtimeMinutesToBeCompensatedUntilThisDay;
+
+
+}
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/persistence/api/WorkingDayRepositoryApi.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/persistence/api/WorkingDayRepositoryApi.java
new file mode 100644
index 0000000..422b299
--- /dev/null
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/persistence/api/WorkingDayRepositoryApi.java
@@ -0,0 +1,8 @@
+package org.nanoboot.utils.timecalc.persistence.api;
+
+/**
+ * @author Robert
+ * @since 23.02.2024
+ */
+public interface WorkingDayRepositoryApi {
+}
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/persistence/impl/sqlite/WorkingDayRepositorySQLiteImpl.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/persistence/impl/sqlite/WorkingDayRepositorySQLiteImpl.java
new file mode 100644
index 0000000..ccc6312
--- /dev/null
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/persistence/impl/sqlite/WorkingDayRepositorySQLiteImpl.java
@@ -0,0 +1,10 @@
+package org.nanoboot.utils.timecalc.persistence.impl.sqlite;
+
+import org.nanoboot.utils.timecalc.persistence.api.WorkingDayRepositoryApi;
+
+/**
+ * @author Robert
+ * @since 23.02.2024
+ */
+public class WorkingDayRepositorySQLiteImpl implements WorkingDayRepositoryApi {
+}
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/AnalogClock.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/AnalogClock.java
index bc9e4fe..8509a18 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/AnalogClock.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/AnalogClock.java
@@ -1,7 +1,7 @@
 package org.nanoboot.utils.timecalc.swing.progress;
 
 import org.nanoboot.utils.timecalc.swing.common.Widget;
-import org.nanoboot.utils.timecalc.main.TimeCalcConf;
+import org.nanoboot.utils.timecalc.app.TimeCalcConf;
 import org.nanoboot.utils.timecalc.utils.DateFormats;
 import org.nanoboot.utils.timecalc.utils.TimeHM;
 import org.nanoboot.utils.timecalc.utils.Utils;
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/Battery.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/Battery.java
index 2b1c080..118ec2f 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/Battery.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/swing/progress/Battery.java
@@ -2,7 +2,7 @@ package org.nanoboot.utils.timecalc.swing.progress;
 
 import lombok.Getter;
 import org.nanoboot.utils.timecalc.swing.common.Widget;
-import org.nanoboot.utils.timecalc.main.TimeCalcConf;
+import org.nanoboot.utils.timecalc.app.TimeCalcConf;
 import org.nanoboot.utils.timecalc.utils.BooleanProperty;
 import org.nanoboot.utils.timecalc.utils.NumberFormats;
 import org.nanoboot.utils.timecalc.utils.Utils;
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Jokes.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Jokes.java
index e72e9f5..58712b3 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Jokes.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Jokes.java
@@ -1,7 +1,7 @@
 package org.nanoboot.utils.timecalc.utils;
 
 import org.nanoboot.utils.timecalc.swing.common.Toaster;
-import org.nanoboot.utils.timecalc.main.TimeCalcConf;
+import org.nanoboot.utils.timecalc.app.TimeCalcConf;
 
 import javax.swing.JFrame;
 import javax.swing.JTextPane;
diff --git a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Utils.java b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Utils.java
index 94095c9..b661659 100644
--- a/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Utils.java
+++ b/modules/time-calc-app/src/main/java/org/nanoboot/utils/timecalc/utils/Utils.java
@@ -1,6 +1,6 @@
 package org.nanoboot.utils.timecalc.utils;
 
-import org.nanoboot.utils.timecalc.main.Main;
+import org.nanoboot.utils.timecalc.app.Main;
 
 import java.awt.Color;
 import java.io.File;