class Student
{
    public String name;
    public int age; 
}

import java.lang.reflect.Field;

/**
 *
 * Getting and Setting Field Values.
 *
 */
public class ReflectionDemo
{
    public static void main(String[] args)
    {
        try
        {
            Class<Student> classObj = Student.class;
            /*
             * Returns:the Field object of this class specified by name
             */
            Field ageField = classObj.getField("age");
            System.out.println("Field Name = " + ageField.getName());
            System.out.println("Field Type = " + ageField.getType());

            Student student = classObj.newInstance();
            /*
             * Sets the field represented by this Field object on the specified
             * object argument to the specified new value.
             */
            ageField.set(student, 23);
            Object ageValue = ageField.get(student);
            System.out.println("age =  "+ageValue);
        }
        catch (NoSuchFieldException | SecurityException
                | IllegalArgumentException | IllegalAccessException
                | InstantiationException e)
        {
            e.printStackTrace();
        }
    }

}