static final long serialVersionUID = 1L
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What is a serialVersionUID and why should I use it?
what is meant by that in a servlet (private static final long serialVersionUID = 1L)?
I have 1 simple question about this guided program given by our professor.
I have seen serialVersionUID several times but I dont what's that for.
package module;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* @author JA
*
*/
public class Servlet_1 extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet{
static final long serialVersionUID = 1L;
public void doGet (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("txt/html");
ServletOutputStream out = response.getOutputStream();
out.println("<html>");
out.println("<head><title>Hello Panget</title></head>");
out.println("<body>");
out.println("<h1>Hello Panget</h1>");
out.println("</body></html>");
}
protected void doPost (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// Write your program here, Panget.
}
}
What is the use of
static final long serialVersionUID = 1L;
in the program?
The serialVersionUID is a universal version identifier for a Serializable class. Deserialization uses this number to ensure that a loaded class corresponds exactly to a serialized object. If no match is found, then an InvalidClassException is thrown.
This is why:
http://frequal.com/java/PracticalSerialVersionIdGuidelines.html
It's not mandatory, but should be added if possible. doesn't hurt though.
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