Bug 121111 Bad event handler class name does not cause an error
Open a report design, open any Data Set's Property editor. Type in an invalid Java class name for the "Event Handler Class" property, say "aaa". Preview a report that uses that Data Set. The report executes normally. No error is shown. Event handlers are an integral part of a report design, and if a script handler class is not found, or if the handler throws a runtime exception, Report Engine should either stop the report execution, or show the error message in the generated report. (Tested with the 2005-12-15 nightly build)
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExecutionContext.java
* @param expr
	 *            the expression to be evaluated
	 * @param name
	 *            the file name
	 * @param lineNo
	 *            the line number
	 * 
	 * @return the result if no error exists, otherwise null.
	 */
	public Object evaluate( String expr, String name, int lineNo )
	{
		if ( expr != null )
		{
			try
			{
				return scriptContext.eval( expr, name, lineNo );
			}
			catch ( Exception e )
			{
				
				
				log.log( Level.SEVERE, e.getMessage( ), e );
				addException( new EngineException(
						MessageConstants.SCRIPT_EVALUATION_ERROR, expr, e ) ); 
			}
		}
		return null;
	}
	/**
	 * @param expr