Name: sgC58550 Date: 03/17/97


When serializing a hashtable containing large strings (100k etc),
the following exception is generated:

java.io.UTFDataFormatException
        at java.io.DataOutputStream.writeUTF(DataOutputStream.java:310)
        at java.io.ObjectOutputStream.writeUTF(ObjectOutputStream.java:1032)
        at java.io.ObjectOutputStream.outputString(ObjectOutputStream.java:480)
        at java.io.ObjectOutputStream.checkSpecialClasses(ObjectOutputStream.java:301)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:182)
        at java.util.Hashtable.writeObject(Hashtable.java:406)
        at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:629)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:225)

The documentation states that writeUTF stores the length of the
string in 2 bytes. This suggests a limit of 32000 characters in
a string.

This is clearly a bug in serializtion, but it could also be
argued that the implementation of writeUTF is rather naive :)

company - , email - ###@###.###
======================================================================


the following programm shows the problem:
If the String is bigger (or equal) than 64 kB, there
is an exception thrown by writeObject:

> java t >/dev/null
write-exception: java.io.UTFDataFormatException

------- t.java -------

public class t {
   public static void main(String arg[]) {
      String s="", a="test";
      for (int i=0; i<256*64; i++)
         s=s+a;
      try {
         new ObjectOutputStream(System.out).writeObject(s);
      } catch (IOException e) {
         System.err.println("write-exception: "+e);
      }
   }
};

company - , email - ###@###.###
=======================================================================