--- a/src/share/classes/com/sun/tools/javac/comp/Lower.java	Sat Sep 18 14:24:09 2010 -0700
+++ b/src/share/classes/com/sun/tools/javac/comp/Lower.java	Wed Sep 22 20:53:34 2010 +0530
@@ -2679,7 +2679,8 @@
     }
 //where
         private JCTree convert(JCTree tree, Type pt) {
-            if (tree.type == pt) return tree;
+            if (tree.type == pt || tree.type.tag == TypeTags.BOT)
+                return tree;
             JCTree result = make_at(tree.pos()).TypeCast(make.Type(pt), (JCExpression)tree);
             result.type = (tree.type.constValue() != null) ? cfolder.coerce(tree.type, pt)
                                                            : pt;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/tools/javac/T6587674.java	Wed Sep 22 20:53:34 2010 +0530
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 6587674
+ * @summary NoClassdefFound when anonymously extending a class.
+ */
+
+import java.util.Vector;
+
+public class T6587674 {
+    private static final Vector<String> list =
+        true ? null : new Vector<String>() { };
+
+    public static void main(String[] args) {
+        System.out.println("T6587674 runs fine!");
+    }
+}