I tried the below code but multiple instances are being created

Question

I m using A.java for initializing the driver to use for test classes.I have used @BeforeCLass
   public class A{

        static WebDriver driver;

        @BeforeClass
        public void returnDriver(){
            driver = //I used other method to initiate and return the driver to here 
        }
    }

Extending Above class to Test classes

public class A1 extends A{

    public A1(){
        returnDriver();
    }
    @Test
    public void a(){
    }
    @Test
    public void b(){
    }

public class B1 extends A{

    public B1(){
        returnDriver();
    }
    @Test
    public void a1(){
    }
    @Test
    public void b1(){
    }

When I execute the code, by default multiple browser instances starts running 

Answer 1

Remove the driver initialization from @BeforeClass/ returnDriver() method and move it to class level.
Use @AfterClass annotation and close the browser.
Use @BeforeSuite instead of @BeforeClass
Use any of the above methods.