Sets the value of the field in the specified object to the
longvalue. This reproduces the effect of
object.fieldName = value
If this field is static, the object argument is ignored.
Otherwise, if the object is
null, a NullPointerException is
thrown. If the object is not an instance of the declaring class of the
method, an IllegalArgumentException is thrown.
If this Field object is enforcing access control (see AccessibleObject)
and this field is not accessible from the current context, an
IllegalAccessException is thrown.
If the value cannot be converted to the field type via a widening
conversion, an IllegalArgumentException is thrown.