deserialization of HashSet fails

[tseytlin]

I have a program that uses the original JDBM and I am trying to port it to JDBM3.
My use case is to use String as a key and either HashSet of Strings or a custom Java object as a value.

When I substitute JDBM3 code I get an error related to object serealiation
Exception in thread "Thread-0" java.lang.InternalError: Unknown serialization header: 97
at org.apache.jdbm.Serialization.deserialize(Serialization.java:962)
at org.apache.jdbm.Serialization.deserializeArrayList(Serialization.java:1136)
at org.apache.jdbm.Serialization.deserialize(Serialization.java:919)
at org.apache.jdbm.Serialization.deserialize(Serialization.java:623)
at org.apache.jdbm.DBStore.fetch2(DBStore.java:400)
at org.apache.jdbm.DBStore.fetch(DBStore.java:366)
at org.apache.jdbm.DBCacheRef.fetch(DBCacheRef.java:213)
at org.apache.jdbm.BTreeLazyRecord.get(BTreeLazyRecord.java:28)
at org.apache.jdbm.HTreeBucket.getValue(HTreeBucket.java:219)
at org.apache.jdbm.HTreeDirectory.get(HTreeDirectory.java:160)
at org.apache.jdbm.HTree.get(HTree.java:199)
at org.apache.jdbm.HTree.containsKey(HTree.java:248)
at edu.pitt.terminology.util.JDBMMap.containsKey(JDBMMap.java:83)

Which looks like it is trying to deserealize HashSet as an ArrayList.

Here is my initialization code:

// init record manager
    DBMaker d = DBMaker.openFile(filename);
    // set options
    d.disableTransactions();
    d.closeOnExit();
    d.enableHardCache();
    d.disableLocking();

    db = d.make();

    // create or load hashtable from given file
    map = db.getTreeMap(tablename);
    if(map == null)
        map = db.createTreeMap(tablename);

Here is where I invoke a wrapper function
Set termList = new HashSet(filterTerms(word,terms));
if(wordMap.containsKey(word)){
termList.addAll(getWordTerms(word));
}
wordsMap.put(word,termList);

It fails on containsKey() line, however I have a hunch that the issue is with serializing HashSet incorrectly.

[tseytlin]

Sorry for the post. I resolved this issue. It had to do with me wanting to use the same file for multiple tables, like I did it in JDBM v1. Once each table got its own file, it worked.

I did encounter issues though with serializing Objects that contained arrays of String. When I switched arrays to Lists it worked.

[jankotek]

I like problems which solve themselves :-)