diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index fe7a72f..652c4e1 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -1,32 +1,22 @@
-# This workflow will build a Java project with Maven, and cache/restore any dependencies to improve the workflow execution time
-# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-java-with-maven
+name: Maven build and test
 
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-
-
-name: Java CI with Maven
-
-on: [push, pull_request]
+on:
+  push:
+  pull_request:
 
 jobs:
   build:
-    permissions: write-all
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
-    - name: Set up JDK 17
-      uses: actions/setup-java@v3
-      with:
-        java-version: '17'
-        distribution: 'zulu'
-        cache: maven
+      - uses: actions/checkout@v4
 
-    - name: Build with Maven
-      run: mvn -B package --file pom.xml
+      - name: Configure JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+          cache: maven
 
-    - name: Run the Maven verify phase
-      run: mvn --batch-mode --update-snapshots verify
+      - name: Compile and run tests
+        run: mvn -B clean test
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..434dfcf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+target/
+.idea/
+*.iml
+.classpath
+.project
+.settings/
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..da42197
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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>my-app</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>my-app</name>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.release>17</maven.compiler.release>
+        <junit.version>5.11.4</junit.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.13.0</version>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.5.2</version>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/src/main/java/com/mycompany/app/App.java b/src/main/java/com/mycompany/app/App.java
new file mode 100644
index 0000000..a83b6da
--- /dev/null
+++ b/src/main/java/com/mycompany/app/App.java
@@ -0,0 +1,12 @@
+package com.mycompany.app;
+
+public class App
+{
+   public static void main(String[] args)
+   {
+      double val=Double.parseDouble("2.0");
+      Sqrt sqrt=new Sqrt(val);
+      double result=sqrt.calc();
+      System.out.println("Sqrt of " + val + " = " + result);
+   }
+}
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..0c1f37a
--- /dev/null
+++ b/src/main/java/com/mycompany/app/Sqrt.java
@@ -0,0 +1,29 @@
+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/SqrtTest.java b/src/test/java/com/mycompany/app/SqrtTest.java
new file mode 100644
index 0000000..140d811
--- /dev/null
+++ b/src/test/java/com/mycompany/app/SqrtTest.java
@@ -0,0 +1,80 @@
+package com.mycompany.app;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class SqrtTest {
+
+    private Sqrt sqrt;
+
+    @BeforeEach
+    void init() {
+        sqrt = new Sqrt(25.0);
+    }
+
+    @Test
+    void averageReturnsHalfSum() {
+        assertEquals(5.5, sqrt.average(4.0, 7.0), 1e-12);
+    }
+
+    @Test
+    void averageForEqualOperands() {
+        assertEquals(3.0, sqrt.average(3.0, 3.0), 1e-12);
+    }
+
+    @Test
+    void goodIsTrueForAccurateGuess() {
+        assertTrue(sqrt.good(5.0, 25.0));
+    }
+
+    @Test
+    void goodIsFalseForInaccurateGuess() {
+        assertFalse(sqrt.good(4.0, 25.0));
+    }
+
+    @Test
+    void improveProducesBetterApproximation() {
+        double refined = sqrt.improve(2.0, 9.0);
+        assertEquals(3.25, refined, 1e-12);
+    }
+
+    @Test
+    void iterStopsOnSuitableGuess() {
+        assertEquals(7.0, sqrt.iter(7.0, 49.0), 1e-9);
+    }
+
+    @Test
+    void iterConvergesToRoot() {
+        assertEquals(5.0, sqrt.iter(1.0, 25.0), 1e-6);
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+            "1.0, 1.0",
+            "4.0, 2.0",
+            "9.0, 3.0",
+            "16.0, 4.0"
+    })
+    void calcForSquareNumbers(double argument, double expectedRoot) {
+        assertEquals(expectedRoot, new Sqrt(argument).calc(), 1e-6);
+    }
+
+    @Test
+    void calcForIrrationalRoot() {
+        double root = new Sqrt(2.0).calc();
+        assertEquals(Math.sqrt(2.0), root, 1e-7);
+    }
+
+    @Test
+    void calcForZero() {
+        Sqrt zeroSqrt = new Sqrt(0.0);
+        double result = zeroSqrt.calc();
+        assertTrue(zeroSqrt.good(result, 0.0));
+    }
+}