**pom.xml**
```xml
<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.example.solution</groupId>
    <artifactId>solution</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <!-- JUnit dependency for testing -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>
```

**src/main/java/com/example/solution/Solution.java**
```rust
package com.example.solution;

public class Solution {
    public int solution(int a, int b) {
        return a * b;
    }
}
```

**src/test/java/com/example/solution/SolutionTest.java**
```rust
package com.example.solution;

import org.junit.Test;
import static org.junit.Assert.*;

public class SolutionTest {

    @Test
    public void testSolution() {
        Solution sol = new Solution();
        assertEquals(6, sol.solution(2, 3));
        assertEquals(0, sol.solution(0, 5));
        assertEquals(-15, sol.solution(-3, 5));
        assertEquals(12, sol.solution(-4, -3));
    }
}
```

**Compile**
```bash
mvn clean compile
```

**Test**
```bash
mvn test
```