String/Hashtable bootstrapping problem

[Eric Blake]

> I have encountered a problem trying to initialize the String and Hashtable
> classes.  Here's the problem:
>
> - Hashtable uses String constants like "loadFactor" and "threshold" which
>   are initialized in Hashtable.<clinit>.
> - String constants are supposed to have unique values, as ensured
>   by String.intern.  Thus, for String constant pool entries, I call
>   String.intern.
> - String.intern makes use of String.internTable, which is a Hashtable,
>   and which is initialized in String.<clinit>.

In a later message,
> I'm talking about these lines from java.util.Hashtable:
>
>   // used for serializing instances of this class
>   private static final ObjectStreamField[] serialPersistentFields =
>     { new ObjectStreamField("loadFactor", float.class),
>       new ObjectStreamField("threshold", int.class) };

I'm a little late entering this conversation, but how about this for a
solution?

Don't use String constants that need to be intern()'d in the <clinit> of
Hashtable.  Instead, explicitly create all Strings needed during bootstrap
via the String(char[]) constructor.  Provided that ObjectStreamField in turn
does not intern() the strings, you are set.

    // used for serializing instances of this class.  Note: since
String.intern()
    // relies on Hashtable during the bootstrap process, we cannot use
string
    // literals here.
    private static final ObjectStreamField[] serialPersistentFields =
      { new ObjectStreamField(new String(
            new char[] {'l','o','a','d','F','a','c','t','o','r'}),
float.class),
        new ObjectStreamField(new String(
            new char[] {'t','h','r','e','s','h','o','l','d'}), int.class) };


--
Eric Blake, Elixent, Castlemead, Lwr Castle St., Bristol BS1 3AG, UK
address@hidden   tel:+44(0)117 917 5611