reflection problem

hi all, i got a problem with this bunch of code:

[CODE]
Manager boss = new Manager("Paul Brown", 1000, 500);

Class c = boss.getClass();

try
{
Field field = c.getField("bonus");

Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus);

}
catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();
}
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();
}
[/CODE]

i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:

Integer newBonus = field.getInt(boss);

[CODE]Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)[/CODE]

illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)