### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: model/org/eclipse/jdt/internal/core/JavaProject.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/JavaProject.java,v
retrieving revision 1.370
diff -u -r1.370 JavaProject.java
--- model/org/eclipse/jdt/internal/core/JavaProject.java	2 May 2006 15:01:33 -0000	1.370
+++ model/org/eclipse/jdt/internal/core/JavaProject.java	1 Dec 2006 06:50:06 -0000
@@ -2740,6 +2740,15 @@
 	}
 
 	/**
+	 * Clear all classpath markers and check the classpath again.
+	 * Add markers for any problems that still remain.
+	 */
+	public void recomputeClasspathProblemMarkers() {
+		flushClasspathProblemMarkers(true, true);
+		updateClasspathMarkers(null, null);
+	}
+	
+	/**
 	 * Removes the given builder from the build spec for the given project.
 	 */
 	protected void removeFromBuildSpec(String builderID) throws CoreException {
Index: model/org/eclipse/jdt/internal/core/builder/JavaBuilder.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/builder/JavaBuilder.java,v
retrieving revision 1.122
diff -u -r1.122 JavaBuilder.java
--- model/org/eclipse/jdt/internal/core/builder/JavaBuilder.java	6 Apr 2006 19:15:52 -0000	1.122
+++ model/org/eclipse/jdt/internal/core/builder/JavaBuilder.java	1 Dec 2006 06:50:06 -0000
@@ -600,6 +600,10 @@
 
 	// Abort build only if there are classpath errors
 	if (isClasspathBroken(javaProject.getRawClasspath(), currentProject)) {
+		// second chance - compilation participants might have fixed a problem during initializeBuilder()
+		javaProject.recomputeClasspathProblemMarkers();
+	}
+	if (isClasspathBroken(javaProject.getRawClasspath(), currentProject)) {
 		if (DEBUG)
 			System.out.println("Aborted build because project has classpath errors (incomplete or involved in cycle)"); //$NON-NLS-1$