diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..020a164
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,35 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.mycompany.app</groupId>
+    <artifactId>ST-5</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.10.2</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.2.5</version>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>
diff --git a/src/main/java/com/mycompany/app/Sqrt.java b/src/main/java/com/mycompany/app/Sqrt.java
new file mode 100644
index 0000000..3fc384a
--- /dev/null
+++ b/src/main/java/com/mycompany/app/Sqrt.java
@@ -0,0 +1,40 @@
+package com.mycompany.app;
+
+public class Sqrt
+{
+    double delta = 0.00000001;
+    double arg;
+
+    public Sqrt(double arg)
+    {
+        this.arg = arg;
+    }
+
+    public double average(double x, double y)
+    {
+        return (x + y) / 2.0;
+    }
+
+    public boolean good(double guess, double x)
+    {
+        return Math.abs(guess * guess - x) < delta;
+    }
+
+    public double improve(double guess, double x)
+    {
+        return average(guess, x / guess);
+    }
+
+    public double iter(double guess, double x)
+    {
+        if (good(guess, x))
+            return guess;
+        else
+            return iter(improve(guess, x), x);
+    }
+
+    public double calc()
+    {
+        return iter(1.0, arg);
+    }
+}
diff --git a/src/test/java/com/mycompany/app/AppTest.java b/src/test/java/com/mycompany/app/AppTest.java
new file mode 100644
index 0000000..5a548ca
--- /dev/null
+++ b/src/test/java/com/mycompany/app/AppTest.java
@@ -0,0 +1,91 @@
+package com.mycompany.app;
+
+import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Test;
+
+public class AppTest
+{
+    @Test
+    void testAverage1()
+    {
+        Sqrt s = new Sqrt(4);
+        assertEquals(3.0, s.average(2, 4), 0.0001);
+    }
+
+    @Test
+    void testAverage2()
+    {
+        Sqrt s = new Sqrt(9);
+        assertEquals(5.0, s.average(4, 6), 0.0001);
+    }
+
+    @Test
+    void testGoodTrue()
+    {
+        Sqrt s = new Sqrt(4);
+        assertTrue(s.good(2.0, 4.0));
+    }
+
+    @Test
+    void testGoodFalse()
+    {
+        Sqrt s = new Sqrt(4);
+        assertFalse(s.good(1.0, 4.0));
+    }
+
+    @Test
+    void testImprove1()
+    {
+        Sqrt s = new Sqrt(4);
+        assertEquals(2.5, s.improve(1.0, 4.0), 0.0001);
+    }
+
+    @Test
+    void testImprove2()
+    {
+        Sqrt s = new Sqrt(9);
+        assertEquals(5.0, s.improve(1.0, 9.0), 0.0001);
+    }
+
+    @Test
+    void testIter4()
+    {
+        Sqrt s = new Sqrt(4);
+        assertEquals(2.0, s.iter(1.0, 4.0), 0.0001);
+    }
+
+    @Test
+    void testIter9()
+    {
+        Sqrt s = new Sqrt(9);
+        assertEquals(3.0, s.iter(1.0, 9.0), 0.0001);
+    }
+
+    @Test
+    void testCalc2()
+    {
+        Sqrt s = new Sqrt(2);
+        assertEquals(Math.sqrt(2), s.calc(), 0.0001);
+    }
+
+    @Test
+    void testCalc4()
+    {
+        Sqrt s = new Sqrt(4);
+        assertEquals(2.0, s.calc(), 0.0001);
+    }
+
+    @Test
+    void testCalc16()
+    {
+        Sqrt s = new Sqrt(16);
+        assertEquals(4.0, s.calc(), 0.0001);
+    }
+
+    @Test
+    void testCalc25()
+    {
+        Sqrt s = new Sqrt(25);
+        assertEquals(5.0, s.calc(), 0.0001);
+    }
+}