diff --git a/Bibliotheksverwaltung/src/DomainLayer/User.java b/Bibliotheksverwaltung/src/DomainLayer/User.java
new file mode 100644
index 0000000..24ded85
--- /dev/null
+++ b/Bibliotheksverwaltung/src/DomainLayer/User.java
@@ -0,0 +1,47 @@
+package DomainLayer;
+
+public abstract class User {
+	private String cardNumber;
+	private String name;
+	private double fees;
+
+	public User(String cardNumber, String name) {
+		this.cardNumber = cardNumber;
+		this.name = name;
+		this.fees = 0.0;
+	}
+
+	// Getter und Setter
+	public String getCardNumber() {
+		return cardNumber;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public double getFees() {
+		return fees;
+	}
+
+	public void addFees(double amount) {
+		this.fees += amount;
+	}
+
+	public void payFees(double amount) {
+		this.fees -= amount;
+	}
+
+	public abstract double calculateAnnualFee();
+}
+
+class AdultUser extends User {
+	public AdultUser(String cardNumber, String name) {
+		super(cardNumber, name);
+	}
+
+	@Override
+	public double calculateAnnualFee() {
+		return 50.0;
+	}
+}
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