Bug 211004 Failed to remove temp db directory after running multiple reports
Description: I use Report Engine API to do runAndrender, run and dataextract tasks on multiple reports. Before the Platform started, I change the temp folder(System.setProperty( "java.io.tmpdir", TEMP_HOME )). Each task is closed after it finished and I shutdown the Platform after all the tasks finished. In log I found "Fail to remove one or more file in temp db directory,but it will be removed when the VM exits: D:\BIRT_NG\temp/BIRTSampleDB_1196129572031_10a6ae2". In temp folder the BIRTSampleDB_XXX is still here but not removed. I think it is the issue when remove the Temp sampleDB. Build number: 2.3.0.v20071127-0630
data/org.eclipse.birt.report.data.oda.sampledb/src/org/eclipse/birt/report/data/oda/sampledb/SampleDBJDBCConnectionFactory.java
Properties props;
		if ( connectionProperties != null )
			props = (Properties)connectionProperties.clone();
		else 
			props = new Properties(); 
		props.put( "user", SampleDBConstants.SAMPLE_DB_SCHEMA);
		props.put( "password", "" );
		
		if ( logger.isLoggable( Level.FINE ))
		{
			logger.fine( "Getting Sample DB JDBC connection. DriverClass=" + 
					SampleDBConstants.DERBY_DRIVER_CLASS + ", Url=" + dbUrl);
		}
		initClassLoaders();
		
		return getDerbyDriver().connect( dbUrl, props);
	}
	
	/**
	 * Sets up the thread context class loader to make sure that Derby works with our class loader
	 */
	private void initClassLoaders()
	{
		if ( derbyClassLoader == null )
		{
			
			derbyClassLoader = new DerbyClassLoader();
		}