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From "Tony Wu" <wuyue...@gmail.com>
Subject Re: svn commit: r480871 - in /harmony/enhanced/classlib/trunk/modules/luni/src: main/java/java/lang/ProcessBuilder.java main/java/org/apache/harmony/luni/platform/Environment.java test/java/org/apache/harmony/luni/tests/java/lang/SystemTest.java
Date Tue, 05 Dec 2006 02:04:19 GMT
And AFAIK, the value is generated according to the field of the class.
So is it correct that the generated SID will be 1L if no field
present?

On 12/5/06, Nathan Beyer <nbeyer@gmail.com> wrote:
> That's not a magic value. A serial version UID of 1 is considered, by
> some, a default value. I know that within a Eclipse, you can either
> generate a value (ala serialver tool) or insert the default value
> (1L).
>
> The serial version UID is an arbitrary value that's meant to be a
> marker for a given class if two serialized objects are compatible.
> Using small iterative values (1, 2, etc) is really no different than
> using a complex weighted calculation that changes when the class
> changes. As long as the number changes or doesn't change for a given
> class, then the compatability or incompatibility, respectively, is
> deterministic.
>
> -Nathan
>
> On 12/4/06, Geir Magnusson Jr. <geir@pobox.com> wrote:
> >
> >
> > Alexey Varlamov wrote:
> > > 2006/12/4, Tony Wu <wuyuehao@gmail.com>:
> > >> This class will never be serialized. I think the meanless variable
> > >> here is created to avoid compiler warining.
> > >
> > > How about using @SupressWarnings("serial")? It is more readable IMO.
> >
> > Thank you.  I didn't know what to suggest, but a magic value was
> > misleading w/o a comment...
> >
> > geir
> >
> > >
> > >>
> > >> On 12/1/06, Geir Magnusson Jr. <geir@pobox.com> wrote:
> > >> >
> > >> >
> > >> > liangyx@apache.org wrote:
> > >> > > Author: liangyx
> > >> > > Date: Thu Nov 30 00:19:55 2006
> > >> > > New Revision: 480871
> > >> > >
> > >> > > URL: http://svn.apache.org/viewvc?view=rev&rev=480871
> > >> > > Log:
> > >> > > Apply patch for HARMONY-2356 ([classlib][luni]The Map from
> > >> System.getEnv should throw NullPointerException while get(null) and is
> > >> not modifiable.)
> > >> > >
> > >> > > Modified:
> > >> > >
> > >> harmony/enhanced/classlib/trunk/modules/luni/src/main/java/java/lang/ProcessBuilder.java
> > >>
> > >> > >
> > >> harmony/enhanced/classlib/trunk/modules/luni/src/main/java/org/apache/harmony/luni/platform/Environment.java
> > >>
> > >> > >
> > >> harmony/enhanced/classlib/trunk/modules/luni/src/test/java/org/apache/harmony/luni/tests/java/lang/SystemTest.java
> > >>
> > >> > >
> > >> >
> > >> > > +
> > >> > > +    public static class EnvironmentMap extends HashMap<String,
> > >> String> {
> > >> > > +
> > >> > > +        private static final long serialVersionUID = 1L;
> > >> > > +
> > >> > > +        public EnvironmentMap() {
> > >> > > +            super();
> > >> > > +        }
> > >> > > +
> > >> > > +        public EnvironmentMap(Map<String, String> map)
{
> > >> > > +            super(map);
> > >> > > +        }
> > >> > > +
> > >> > > +        public boolean containsKey(Object key) {
> > >> > > +            checkParam(key);
> > >> > > +            return super.containsKey(key);
> > >> > > +        }
> > >> >
> > >> >
> > >> >
> > >> > I'm curious - why set the ServialVersionUID to 1?
> > >> >
> > >> > geir
> > >> >
> > >>
> > >>
> > >> --
> > >> Tony Wu
> > >> China Software Development Lab, IBM
> > >>
> >
>


-- 
Tony Wu
China Software Development Lab, IBM

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