Bug 202236 When select NULL value for multi-value parameter, cause NPE.
Description: When select NULL value for multi-value parameter, cause NPE. Build number: 2.2.1 Steps to reproduce: 1, New a list parameter, check Allow multi-value, uncheck isRequired 2, Select parameter data type as Date 3, Add some items into list 4, Preview 5, Select Null Value item in list Expected result: Can accept Null value for multi-value parameter Actual result: Cause NPE.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java
/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.api.IRenderTask#setRenderOption(org.eclipse.birt.report.engine.api.IRenderOption)
	 */
	public void setRenderOption( IRenderOption options )
	{
		if ( options == null )
		{
			throw new NullPointerException( "options can't be null" );
		}
		renderOptions = options;
	}
	public IRenderOption getRenderOption( )
	{
		return renderOptions;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.api.IRenderTask#setEmitterID(java.lang.String)
	 */
	/**
	 * @deprecated
	 */
	public void setEmitterID( String id )
	{
		this.emitterID = id;
	}
	/**