Example

public class BeanClass implements javax.ejb.SessionBean {
public String ejbPostCreate () {
//instantiation of bean

return "example primary key";
}

//other methods that must implement the interface
}

Solution
Declare a void return type for the method ejbPostCreate()


public class BeanClass implements javax.ejb.SessionBean {
public void ejbPostCreate () {
//instantiation of bean
}

//other methods that must implement the interface
}