--- a/langtools/src/share/classes/com/sun/tools/javac/comp/DeferredAttr.java	Fri Mar 22 12:39:34 2013 +0000
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/DeferredAttr.java	Fri Mar 22 12:41:13 2013 +0000
@@ -229,9 +229,9 @@
         public Type complete(DeferredType dt, ResultInfo resultInfo, DeferredAttrContext deferredAttrContext) {
             switch (deferredAttrContext.mode) {
                 case SPECULATIVE:
-                    Assert.check(dt.mode == null ||
-                            (dt.mode == AttrMode.SPECULATIVE &&
-                            dt.speculativeType(deferredAttrContext.msym, deferredAttrContext.phase).hasTag(NONE)));
+                    //Note: if a symbol is imported twice we might do two identical
+                    //speculative rounds...
+                    Assert.check(dt.mode == null || dt.mode == AttrMode.SPECULATIVE);
                     JCTree speculativeTree = attribSpeculative(dt.tree, dt.env, resultInfo);
                     dt.speculativeCache.put(deferredAttrContext.msym, speculativeTree, deferredAttrContext.phase);
                     return speculativeTree.type;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/lambda/DoubleStaticImport.java	Fri Mar 22 12:41:13 2013 +0000
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2011, 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 8009820
+ * @summary AssertionError when compiling java code with two identical static imports
+ * @compile DoubleStaticImport.java
+ */
+
+import static java.lang.Thread.holdsLock;
+import static java.lang.Thread.holdsLock; //dup
+
+class DoubleStaticImport {
+    public void test() {
+        holdsLock(null);
+    }
+}