diff --git a/lab2/src/main/java/ru/spbstu/telematics/java/MyTreeSet.java b/lab2/src/main/java/ru/spbstu/telematics/java/MyTreeSet.java
index af0c31e..475e179 100644
--- a/lab2/src/main/java/ru/spbstu/telematics/java/MyTreeSet.java
+++ b/lab2/src/main/java/ru/spbstu/telematics/java/MyTreeSet.java
@@ -20,6 +20,10 @@ public class MyTreeSet<E extends Comparable<E>> {
     }
 
     public boolean add(E element) {
+        if (element == null) {
+            throw new NullPointerException("Нельзя добавить null в TreeSet!");
+        }
+
         if (root == null) {
             root = new Node(element);
             return true;
diff --git a/lab2/src/test/java/ru/spbstu/telematics/java/AppTest.java b/lab2/src/test/java/ru/spbstu/telematics/java/AppTest.java
index fd5e571..1d02c41 100644
--- a/lab2/src/test/java/ru/spbstu/telematics/java/AppTest.java
+++ b/lab2/src/test/java/ru/spbstu/telematics/java/AppTest.java
@@ -18,8 +18,14 @@ class MyTreeSetTests {
 
     @Test
     void testAdd() {
+        assertThrows(NullPointerException.class, () -> myTreeSet.add(null));
+        assertThrows(NullPointerException.class, () -> treeSet.add(null));
+
         assertEquals(myTreeSet.add(150), treeSet.add(150));
         assertEquals(myTreeSet.add(200), treeSet.add(200));
         assertEquals(myTreeSet.add(150), treeSet.add(150));
+
+        assertThrows(NullPointerException.class, () -> myTreeSet.add(null));
+        assertThrows(NullPointerException.class, () -> treeSet.add(null));
     }
 }