diff --git a/spring-5/src/main/java/com/baeldung/assertions/Car.java b/spring-5/src/main/java/com/baeldung/assertions/Car.java
new file mode 100644
index 0000000000..4e210dfaab
--- /dev/null
+++ b/spring-5/src/main/java/com/baeldung/assertions/Car.java
@@ -0,0 +1,122 @@
+package com.baeldung.assertions;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.util.Assert;
+
+public class Car {
+    private String state = "stop";
+
+    public void drive(int speed) {
+        Assert.isTrue(speed > 0, "speed must be positive");
+        this.state = "drive";
+        // ...
+        if (!(speed > 0)) {
+            throw new IllegalArgumentException("speed must be >0");
+        }
+    }
+
+    public void stop() {
+        this.state = "stop";
+    }
+
+    public void fuel() {
+        Assert.state(this.state.equals("stop"), "car must be stopped");
+        // ...
+    }
+
+    public void fuelwithSupplier() {
+        Assert.state(this.state.equals("stop"), () -> "car must be stopped");
+        // ...
+    }
+
+    public void сhangeOil(String oil) {
+        Assert.notNull(oil, "oil mustn't be null");
+        // ...
+    }
+
+    public void сhangeOilWithIsNull(String oil) {
+        Assert.isNull(oil, "oil must be null");
+        // ...
+    }
+
+    public void сhangeEngine(Engine engine) {
+        Assert.isInstanceOf(ToyotaEngine.class, engine);
+        // ...
+    }
+
+    public void repairEngine(Engine engine) {
+        Assert.isAssignable(Engine.class, ToyotaEngine.class);
+        // ...
+    }
+
+    public void startWithHasLength(String key) {
+        Assert.hasLength(key, "key must not be null and must not the empty");
+        // ...
+    }
+
+    public void startWithHasText(String key) {
+        Assert.hasText(key, "key must not be null and must contain at least one non-whitespace  character");
+        // ...
+    }
+
+    public void startWithNotContain(String key) {
+        Assert.doesNotContain(key, "123", "key must not contain 123");
+        // ...
+    }
+
+    public void repair(Collection<String> repairParts) {
+        Assert.notEmpty(repairParts, "collection of repairParts mustn't be empty");
+        // ...
+    }
+
+    public void repair(Map<String, String> repairParts) {
+        Assert.notEmpty(repairParts, "map of repairParts mustn't be empty");
+        // ...
+    }
+
+    public void repair(String[] repairParts) {
+        Assert.notEmpty(repairParts, "array of repairParts must not be empty");
+        // ...
+    }
+
+    public void repairWithNoNull(String[] repairParts) {
+        Assert.noNullElements(repairParts, "array of repairParts must not contain null elements");
+        // ...
+    }
+
+    public static void main(String[] args) {
+        Car car = new Car();
+
+        car.drive(50);
+
+        car.stop();
+
+        car.fuel();
+
+        car.сhangeOil("oil");
+        car.сhangeOilWithIsNull(null);
+
+        car.сhangeEngine(new ToyotaEngine());
+
+        car.startWithHasLength(" ");
+        car.startWithHasText("t");
+        car.startWithNotContain("132");
+
+        List<String> repairPartsCollection = new ArrayList<String>();
+        repairPartsCollection.add("part");
+        car.repair(repairPartsCollection);
+
+        Map<String, String> repairPartsMap = new HashMap<String, String>();
+        repairPartsMap.put("1", "part");
+        car.repair(repairPartsMap);
+
+        String[] repairPartsArray = { "part" };
+        car.repair(repairPartsArray);
+
+    }
+}
diff --git a/spring-5/src/main/java/com/baeldung/assertions/Engine.java b/spring-5/src/main/java/com/baeldung/assertions/Engine.java
new file mode 100644
index 0000000000..40cc161ee4
--- /dev/null
+++ b/spring-5/src/main/java/com/baeldung/assertions/Engine.java
@@ -0,0 +1,4 @@
+package com.baeldung.assertions;
+
+public class Engine {
+}
diff --git a/spring-5/src/main/java/com/baeldung/assertions/ToyotaEngine.java b/spring-5/src/main/java/com/baeldung/assertions/ToyotaEngine.java
new file mode 100644
index 0000000000..21af8df55f
--- /dev/null
+++ b/spring-5/src/main/java/com/baeldung/assertions/ToyotaEngine.java
@@ -0,0 +1,5 @@
+package com.baeldung.assertions;
+
+public class ToyotaEngine extends Engine {
+
+}