Concurrent database access giving IllegalStateException

Question

I am trying to spawn a thread for just 1 method. Im getting an IllegalStateException (see below). What this method does it accept a Connection to a database and the database name, and it will generate XML from it. (That part works I am just trying to make it go faster with a new thread because I have multiple XML files to create.

    Thread table = new Thread(new Runnable() {
    public void run() {
    try {
     System.out.println("starting");
     tableXml(tableConn, dbName);
     System.out.println("ending");
     }
     catch (Exception e) {
      // TODO Auto-generated catch block
        e.printStackTrace();
      }
  }
});

    table.start();

Exception:

java.lang.IllegalStateException: Current state = RESET, new state = FLUSHED
    at java.nio.charset.CharsetEncoder.throwIllegalStateException(CharsetEncoder.java:951)
    at java.nio.charset.CharsetEncoder.flush(CharsetEncoder.java:640)
    at java.nio.charset.CharsetEncoder.encode(CharsetEncoder.java:769)
    at com.informix.lang.JavaToIfxType.doConversion(JavaToIfxType.java:841)
    at com.informix.lang.JavaToIfxType.JavaToIfxChar(JavaToIfxType.java:145)
    at com.informix.jdbc.IfxVarChar.toString(IfxVarChar.java:247)
    at com.informix.jdbc.IfxResultSet.getString(IfxResultSet.java:742)
    at com.informix.jdbc.IfxResultSet.getString(IfxResultSet.java:785)
    at org.apache.commons.dbcp.DelegatingResultSet.getString(DelegatingResultSet.java:225)
    at com.test.ex.ExportTask$1.run(ExportTask.java:151)
    at java.lang.Thread.run(Thread.java:662)

The line of code that is causing the exception is a resultSet.executeQuery();

So the question is: what am I doing wrong?

Thanks for your help, let me know if you need information

Answer 1

It seems that the problem is because your code is not thread safe. Try giving each new thread that is spawned its own connection instead of sharing a reference of a single connection between all threads in your application.