--- a/langtools/src/share/classes/com/sun/tools/javac/code/Types.java	Fri Aug 17 17:30:03 2012 -0700
+++ b/langtools/src/share/classes/com/sun/tools/javac/code/Types.java	Mon Aug 20 21:24:10 2012 +0530
@@ -1589,9 +1589,16 @@
      * type parameters in t are deleted.
      */
     public Type erasure(Type t) {
-        return erasure(t, false);
+        return eraseNotNeeded(t)? t : erasure(t, false);
     }
     //where
+    private boolean eraseNotNeeded(Type t) {
+        // We don't want to erase primitive types and String type as that
+        // operation is idempotent. Also, erasing these could result in loss
+        // of information such as constant values attached to such types.
+        return (t.tag <= lastBaseTag) || (syms.stringType.tsym == t.tsym);
+    }
+
     private Type erasure(Type t, boolean recurse) {
         if (t.tag <= lastBaseTag)
             return t; /* fast special case */

--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Lower.java	Fri Aug 17 17:30:03 2012 -0700
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Lower.java	Mon Aug 20 21:24:10 2012 +0530
@@ -3499,7 +3499,6 @@
                 JCExpression expression = oneCase.getExpression();
 
                 if (expression != null) { // expression for a "default" case is null
-                    expression = TreeInfo.skipParens(expression);
                     String labelExpr = (String) expression.type.constValue();
                     Integer mapping = caseLabelToPosition.put(labelExpr, casePosition);
                     Assert.checkNull(mapping);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/StringsInSwitch/7181320/BinOpInCaseLabel.java	Mon Aug 20 21:24:10 2012 +0530
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2012, 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     7181320
+ * @summary javac NullPointerException for switch labels with cast to String expressions
+ * @compile BinOpInCaseLabel.java
+ */
+
+public class BinOpInCaseLabel {
+    public static void main(String [] args) {
+        switch (args[0]) {
+            case "hello" + "world":
+                break;
+        }
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/StringsInSwitch/7181320/CastInCaseLabel.java	Mon Aug 20 21:24:10 2012 +0530
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2012, 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     7181320
+ * @summary javac NullPointerException for switch labels with cast to String expressions
+ * @compile CastInCaseLabel.java
+ */
+
+public class CastInCaseLabel {
+    public static void main(String [] args) {
+        switch (args[0]) {
+            case (String)"hello":
+                break;
+        }
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/StringsInSwitch/7181320/CondExprInCaseLabel.java	Mon Aug 20 21:24:10 2012 +0530
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2012, 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     7181320
+ * @summary javac NullPointerException for switch labels with cast to String expressions
+ * @compile CondExprInCaseLabel.java
+ */
+
+public class CondExprInCaseLabel {
+    public static void main(String [] args) {
+        final boolean cond = true;
+        switch (args[0]) {
+            case cond ? "hello" : "world":
+                break;
+        }
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/StringsInSwitch/7181320/CondExprInCaseLabel1.java	Mon Aug 20 21:24:10 2012 +0530
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2012, 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     7181320
+ * @summary javac NullPointerException for switch labels with cast to String expressions
+ * @compile CondExprInCaseLabel1.java
+ */
+
+public class CondExprInCaseLabel1 {
+    public static void main(String [] args) {
+        final boolean cond = true;
+        switch (args[0]) {
+            case cond ? (String)"hello" : "world":
+                break;
+        }
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/StringsInSwitch/7181320/CondExprInCaseLabel2.java	Mon Aug 20 21:24:10 2012 +0530
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2012, 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     7181320
+ * @summary javac NullPointerException for switch labels with cast to String expressions
+ * @compile CondExprInCaseLabel2.java
+ */
+
+public class CondExprInCaseLabel2 {
+    public static void main(String [] args) {
+        final boolean cond = true;
+        switch (args[0]) {
+            case cond ? "hello" : (String)"world":
+                break;
+        }
+    }
+}