What does {id} mean/do in #RequestMapping(value = "/delete/{id}") - spring

Question

I'm currently in the process of learning Spring and I keep bumping into that in various examples but I haven't found any explanation anywhere
I've also found
return "redirect:/delete/{id}"
I understand id is a variable, but what does it do. what is the difference between
#RequestMapping(value = "/delete/{id}")
and
#RequestMapping(value = "/delete")
Taken from this example http://www.javainterviewpoint.com/spring-mvc-crud-example-mysql/
Controller
#RequestMapping(value = "/delete/{id}")
public ModelAndView deleteEmployee(#ModelAttribute("employee") Employee employee,#PathVariable("id") int id)
{
employeeDAO.deleteEmployee(id);
return new ModelAndView("redirect:/employees");
}
Model
package com.javainterviewpoint;
import java.io.Serializable;
public class Employee implements Serializable
{
private static final long serialVersionUID = -1280037900360314186L;
private Integer id;
private String name;
private Integer age;
private String dept;
public Employee()
{
super();
}
public Employee(Integer id, String name, Integer age, String dept)
{
super();
this.id = id;
this.name = name;
this.age = age;
this.dept = dept;
}
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
this.id = id;
}

Answer 1

#RequestMapping(value = "/delete/{id}") mean that you can delete employee with specifc id. The full request can be for example: http://yourSite.com/delete/42
Then you can see #PathVariable("id") int id - it's mean variable id will be contain value from url.
With this aproach you can do something like this:
/doSomething/{someUserName}/{someValue}/{someId}
and you will have:
#PathVariable("someUserName") String someUserName, #PathVariable("someValue") String id, #PathVariable("id") int id
Another example:

Answer 2

It's a PathVariable and you can use it for example when you have users and you to need to edit or delete one user. This will tell to spring method on which user you have clicked.
You can read the section URI Template Pattern of Spring MVC guide for more clarifications.
With this approach you attach the id of the user to the url you are calling, and Spring will map the id found in url to the variable you define in method deleteEmployee (#PathVariable("id") int id)
For example you can invoke deleteEmployee method with this url:
http://yourUrl/delete/12345
Then employeeDAO.deleteEmployee(id); call will be executed with 12345 as id