DATACMNS-640 - Fixed potential NullPointerException in PageableHandlerMethodArgumentResolver.

We now double check the fallback Pageable for being null before trying to lookup the Sort to fall back.

Author: odrotbohm

src/main/java/org/springframework/data/web/PageableHandlerMethodArgumentResolver.java

@@ -246,7 +246,11 @@ public Pageable resolveArgument(MethodParameter methodParameter, ModelAndViewCon
 		pageSize = pageSize > maxPageSize ? maxPageSize : pageSize;
 
 		Sort sort = sortResolver.resolveArgument(methodParameter, mavContainer, webRequest, binderFactory);
-		return new PageRequest(page, pageSize, sort == null ? defaultOrFallback.getSort() : sort);
+
+		// Default if necessary and default configured
+		sort = sort == null && defaultOrFallback != null ? defaultOrFallback.getSort() : sort;
+
+		return new PageRequest(page, pageSize, sort);
 	}
 
 	/**

src/test/java/org/springframework/data/web/PageableHandlerMethodArgumentResolverUnitTests.java

@@ -216,6 +216,26 @@ public void considersOneIndexedParametersSetting() {
 				.getPageNumber(), is(0));
 	}
 
+	/**
+	 * @see DATACMNS-640
+	 */
+	@Test
+	public void usesNullSortIfNoDefaultIsConfiguredAndPageAndSizeAreGiven() {
+
+		PageableHandlerMethodArgumentResolver resolver = getResolver();
+		resolver.setFallbackPageable(null);
+
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addParameter("page", "0");
+		request.addParameter("size", "10");
+
+		Pageable result = resolver.resolveArgument(supportedMethodParameter, null, new ServletWebRequest(request), null);
+
+		assertThat(result.getPageNumber(), is(0));
+		assertThat(result.getPageSize(), is(10));
+		assertThat(result.getSort(), is(nullValue()));
+	}
+
 	@Override
 	protected PageableHandlerMethodArgumentResolver getResolver() {
 		PageableHandlerMethodArgumentResolver resolver = new PageableHandlerMethodArgumentResolver();