### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: model/org/eclipse/jdt/core/JavaCore.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/core/JavaCore.java,v
retrieving revision 1.615.2.1
diff -u -r1.615.2.1 JavaCore.java
--- model/org/eclipse/jdt/core/JavaCore.java	1 Dec 2008 16:08:00 -0000	1.615.2.1
+++ model/org/eclipse/jdt/core/JavaCore.java	6 Aug 2009 17:39:29 -0000
@@ -3342,6 +3342,8 @@
 				IClasspathEntry[] classpath;
 				try {
 					classpath = javaProject.getResolvedClasspath();
+					// 285917: force JavaProject.buildStructure to be called if it hasn't yet, to make sure externalLibTimestamps are computed
+					javaProject.getPackageFragmentRoots();
 				} catch (JavaModelException e) {
 					// project no longer exist: ignore
 					continue;