1. how can I use a very long XML files as process variable? the size of these files is variable. It can be more than 6000 lines as UTF8 chars. The process variables are delivered as a string now. If they aren't to big(til 4000 chars), they can be stored in DB(mssql) -> Table ACT_RU_VARIABLE column TEXT.
Another questions to this topic 2. What it the goal of column TEXT2? 3.How can I use Serializable objects?
1: by storing them on a magnetic tape drive and putting the tape id as a small string in a processvariable 2: no idea sorry 3: by just using them. Meaning adding them as a value to a processvariable.
About 1, you should store them as a array of bytes or as a Serializable (other than String). This way a BLOB (or corresponding type) will be used for that variable. Also, http://jira.codehaus.org/browse/ACT-236 will be fixed this release, this will solve this problem I guess.
About 2: TEXT2_ column is used to store another String field, eg. JPAVariable. This will store entity-classname in TEXT1_ and ID in TEXT2_ (if @Id is of type String). About 3: check out org.activiti.examples.variables.VariablesTest, all types of variables are used