ServletConfig config = getServletConfig();
ServletContext context = config.getServletContext();

Example;

public class Java8s extends HttpServlet
{
    public void doGet/doPost()
    {
        //
    }
    ServletContext context = getServletContext();
}

Example;

public class Java8s extends HttpServlet
{
    public void doGet/doPost(HttpServletRequest req,-)
    {
        ServletContext ctx = req.getServletContext();
    }
}

Example;

public class Java8s extends HttpServlet
{
    public void doGet/doPost(HttpServletRequest req,-)
    {
        ServletContext ctx = req.getServletContext();
    }
}

index.html

<form action="MyServlet1" method="post">
    <input type="submit" value="go">
    </form>
</font>

MyServlet1.java

package java8s;
 
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*
public class MyServlet1 extends HttpServlet
{
    protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException,IOException
    {
        response.setContentType("text/html");
 
        PrintWriter pw=response.Writer;
        // I am using 2nd way to create Context object
        ServletContext context=getServletContext();  
 
        String s1=context.getInitParameter("n1");
        String s2=context.getInitParameter("n2");
 
        pw.println("n1 value is " +s1+ " and n2 is " +s2);
 
       pw.close();
    }
}

web.xml

<web-app>
 
    <context-param>
        <param-name> n1 </param-name>
        <param-value> 1000 </param-value>
    </context-param>
 
    <context-param>
        <param-name> n2  </param-name>
        <param-valuev 2000 </param-value>
    /context-param>
 
    <servlet>
        <servlet-name>abc</servlet-name>
        <servlet-class>java8s.MyServlet1</servlet-class>
    </servlet>

    <servlet-mapping>
            <servlet-name>abc</servlet-namev
            <url-pattern>/MyServlet1</url-patternv
    </servlet-mappingv
 
   <welcome-file-listv  
        <welcome-file>index.html</welcome-filev  
   </welcome-file-list>
 
</web-app><web-app>