[Springframework-developer] possible null pointer dereferences x 3 (findbugs)

[Janek B. <ya...@st...>]

findbugs 0.7.1 located 3 possible null pointer dereferences in
spring.jar (RC1). I've pasted the relevant source code here along with a
count of other potential bugs located by findbugs.


Not short circuited logic:

org.springframework.web.servlet.mvc.AbstractWizardFormController.setPages(String[])

	public final void setPages(String[] pages) {
		if (pages == null | pages.length == 0)  {
			throw new IllegalArgumentException("No wizard pages defined");
		}
		this.pages = pages;
	}



viewClass could be null when getName() is invoked:

org.springframework.web.servlet.view.UrlBasedViewResolver.setViewClass(Class)

	public void setViewClass(Class viewClass) {
		if (viewClass == null || !requiredViewClass().isAssignableFrom(viewClass)) {
			throw new IllegalArgumentException("Given View class [" + viewClass.getName() + "] is not of type [" +
                        requiredViewClass().getName() + "]");
		}
		this.viewClass = viewClass;
	}



Should the method exit when factory is found to be undefined?

org.springframework.web.servlet.view.tiles.TilesView.

	protected void renderMergedOutputModel(Map model, HttpServletRequest request,
	                                       HttpServletResponse response) throws Exception {
		if (!response.isCommitted()) {
			response.setContentType(getContentType());
		}
		
		// get definitions factory
		DefinitionsFactory factory = (DefinitionsFactory)
			getWebApplicationContext().getServletContext().
			getAttribute(TilesUtilImpl.DEFINITIONS_FACTORY);
		if (factory == null) {
			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                        "Tiles definitions factory not found: TilesConfigurer not defined?");
		}

		// get component definition
		ComponentDefinition definition = factory.getDefinition(getUrl(), request, getServletContext());



findbugs also noted potential bugs in 11 other categories:

	Dropped or ignored exception: 1
	Dubious method used: 7
	Method returning array may expose internal representation: 15
	Equal objects must have equal hashcodes: 6
	Mutable static field: 7
	Using notify() rather than notifyAll() in method: 1
	Redundant comparison to null: 2
	Should be static inner class: 2
	Incorrect definition of serializable class: 6
	Unread field: 1
	Unused field: 2

I picked the easiest category (potential NPEs) to highlight. Whether the remaining bugs are important or actually bugs at all requires a bit more thought!

-Janek