Bug 155496 Due to inactivity, a group report gives NULL Pointer Exception on selection of TOC and Export CSV option
Steps to reproduce this issue:- 1. Access any Group report that lists groups in TOC 2. For some time do not do any activity on report page (say 15 mins.) 3. Now click on Toggle Table Contents Link 4. The pop window gets opened with following error message java.lang.NullPointerException org.apache.axis.AxisFault.makeFault(AxisFault.java:101) org.eclipse.birt.report.soapengine.processor.AbstractBaseComponentProcessor.process(Unknown Source) org.eclipse.birt.report.soapengine.endpoint.BirtSoapBindingImpl.getUpdatedObjects(Unknown Source) sun.reflect.GeneratedMethodAccessor80.invoke(Unknown Source) When page remains idle for some time the same error gets displayed on selection of Export CSV option. Note:- This issue occurs for the reports that are run using '__overwrite' option. Any help on this is highly appreciated.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
/**
	 * Servlet path for running model.
	 */
	public static final String SERVLET_PATH_DOWNLOAD = "/download"; 
	
	/**
	 * URL parameter name that gives the report design name.
	 */
	public static final String PARAM_REPORT = "__report"; 
	/**
	 * URL parameter name that gives the report document name.
	 */
	public static final String PARAM_REPORT_DOCUMENT = "__document"; 
	/**
	 * URL parameter name that gives the format to display the report, html or
	 * pdf.
	 */
	public static final String PARAM_FORMAT = "__format"; 
	/**
	 * Format parameter constants to display the report in html.
	 */
	public static final String PARAM_FORMAT_HTM = "htm"; 
	public static final String PARAM_FORMAT_HTML = "html"; 
	/**
	 * Format parameter constants to display the report in pdf.
	 */
	public static final String PARAM_FORMAT_PDF = "pdf"; 
	/**
	 * URL parameter name that gives the locale.
	 */