Re: 8028027: serialver should emit declaration with the 'private' modifier

[Stuart Marks]

On 11/8/13 7:20 AM, Yuri Gaevsky wrote:
Well, it would be more consistent to check for existence of protected or public 
serialVersionUID with Reflection API and change the serialver output 
accordingly.

Please see suggested fix and its output below.

This change isn't consistent with the intent of the 'serialver' utility. Its 
intent is to produce a declaration that's "suitable for copying into an evolving 
class." [1] (Clearly, this means the source code of a class.) The spec [2] 
"strongly advises" that serialVersionUID be private. As such, serialver should 
follow the strong advice given in the spec.

If there happens to be a declaration in the class that, probably mistakenly, 
goes against this advice, serialver shouldn't emit a line that perpetuates this 
mistake.

One can use "javap -v" to determine the presence of serialVersionUID field, 
including its modifiers, if that's what's desired.

s'marks

[1] http://docs.oracle.com/javase/7/docs/technotes/tools/solaris/serialver.html

[2] http://docs.oracle.com/javase/7/docs/api/java/io/Serializable.html



Thanks,
-Yuri

$ serialver java.security.PublicKey
java.security.PublicKey:    public static final long serialVersionUID = 
7187392471159151072L;

$ serialver java.lang.Exception
java.lang.Exception:     static final long serialVersionUID = 
-3387516993124229948L;

$ serialver java.lang.AssertionError
java.lang.AssertionError:    private static final long serialVersionUID = 
-5013299493970297370L;

$ serialver javax.xml.ws.soap.SOAPFaultException
javax.xml.ws.soap.SOAPFaultException:    private static final long 
serialVersionUID = -104968645459360720L;


$ hg diff
diff --git a/src/share/classes/sun/tools/serialver/SerialVer.java 
b/src/share/classes/sun/tools/serialver/SerialVer.java
--- a/src/share/classes/sun/tools/serialver/SerialVer.java
+++ b/src/share/classes/sun/tools/serialver/SerialVer.java
@@ -38,6 +38,7 @@
  import java.net.MalformedURLException;
  import java.util.StringTokenizer;
  import sun.net.www.ParseUtil;
+import java.lang.reflect.Modifier;

  public class SerialVer extends Applet {
      GridBagLayout gb;
@@ -211,7 +212,17 @@
          Class<?> cl = Class.forName(classname, false, loader);
          ObjectStreamClass desc = ObjectStreamClass.lookup(cl);
          if (desc != null) {
-            return "    static final long serialVersionUID = " +
+           String ams = "";
+           try {
+               final int mod =
+                       cl.getDeclaredField("serialVersionUID").getModifiers();
+               ams = Modifier.isPublic(mod) ? "public"
+                   : Modifier.isProtected(mod) ? "protected"
+                   : Modifier.isPrivate(mod) ? "private" : "";
+           } catch (NoSuchFieldException nsfe) {
+               ams = "private";
+           }
+            return "    " + ams + " static final long serialVersionUID = " +
                  desc.getSerialVersionUID() + "L;";
          } else {
              return null;