Bug#121636: libgcj2: ObjectInputStream.readObject() calls constructors

[Agthorr <agthorr@barsoom.org>]

Package: libgcj2
Version: 1:3.0.2-3
Severity: normal

The implementation of ObjectInputStream.readObject() in this version
of libgcj calls the constructor of the serialize object it is reading.
Sun's implementation does not do this, nor (I think) did earlier
versions of libgcj.  Below is a sample program which prints "foo" once
with javac, but twice with gcj/libgcj.

I found this while debugging a real program, where it was causing me
quite a bit of confusion.

-- Agthorr

------------------------------------------------------------------------
import java.io.*;

class Break implements Serializable {
        int x;
        
        public Break () {
                System.err.println ("foo");
        }
        
        static public void main (String [] args)
                throws java.io.IOException, java.lang.ClassNotFoundException
        {
                ByteArrayOutputStream bufout = new ByteArrayOutputStream ();
                ObjectOutputStream out = new ObjectOutputStream (bufout);
                Break foo = new Break ();
                foo.x = 5;
                out.writeObject (foo);
                byte [] bytes = bufout.toByteArray ();
                ByteArrayInputStream bufin = new ByteArrayInputStream (bytes);
                ObjectInputStream in = new ObjectInputStream (bufin);
                in.readObject ();
        }

        public String toString () {return Integer.toString (x);}
}
------------------------------------------------------------------------

-- System Information
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux eleutheromania 2.4.12 #1 Fri Oct 12 15:06:20 PDT 2001 i686
Locale: LANG=C, LC_CTYPE=

Versions of packages libgcj2 depends on:
ii  libc6                         2.2.4-5    GNU C Library: Shared libraries an
ii  libgcc1                       1:3.0.2-3  GCC support library.
ii  zlib1g                        1:1.1.3-16 compression library - runtime