8160024: jdb returns invalid argument count if first parameter to Arrays.asList is null

Summary: Adjust com/sun/jdi/MethodImpl.java for null argument
Reviewed-by: dcubed, dsamersoff

src/share/classes/com/sun/tools/jdi/MethodImpl.java

 /*
- * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2016, 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
@@ -315,10 +315,14 @@ public abstract class MethodImpl extends TypeComponentImpl
             return;
         }
         Value nthArgValue = arguments.get(paramCount - 1);
-        if (nthArgValue == null) {
+        if (nthArgValue == null && argCount == paramCount) {
+            // We have one varargs parameter and it is null
+            // so we don't have to do anything.
             return;
         }
-        Type nthArgType = nthArgValue.type();
+        // If the first varargs parameter is null, then don't
+        // access its type since it can't be an array.
+        Type nthArgType = (nthArgValue == null) ? null : nthArgValue.type();
         if (nthArgType instanceof ArrayTypeImpl) {
             if (argCount == paramCount &&
                 ((ArrayTypeImpl)nthArgType).isAssignableTo(lastParamType)) {

test/com/sun/jdi/EvalArraysAsList.sh

+#!/bin/sh
+#
+# Copyright (c) 2016, 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 8160024
+#  @summary jdb returns invalid argument count if first parameter to Arrays.asList is null
+#
+#  @run shell/timeout=300 EvalArraysAsList.sh
+#
+#  The test checks if evaluation of the expression java.util.Arrays.asList(null, "a")
+#  works normally and does not throw an IllegalArgumentException.
+
+classname=EvalArraysAsList
+
+createJavaFile()
+{
+    cat <<EOF > $classname.java.1
+public class $classname {
+    public static void main(String[] args) {
+        java.util.List<Object> l = java.util.Arrays.asList(null, "a");
+        System.out.println("java.util.Arrays.asList(null, \"a\") returns: " + l);
+        return;    // @1 breakpoint
+    }
+}
+EOF
+}
+
+# drive jdb by sending cmds to it and examining its output
+dojdbCmds()
+{
+    setBkpts @1
+    runToBkpt @1
+
+    cmd eval "java.util.Arrays.asList(null, null)"
+    jdbFailIfPresent "IllegalArgumentException" 3
+
+    cmd eval "java.util.Arrays.asList(null, \"a\")"
+    jdbFailIfPresent "IllegalArgumentException" 3
+
+    cmd eval "java.util.Arrays.asList(\"a\", null)"
+    jdbFailIfPresent "IllegalArgumentException" 3
+}
+
+
+mysetup()
+{
+    if [ -z "$TESTSRC" ] ; then
+        TESTSRC=.
+    fi
+
+    for ii in . $TESTSRC $TESTSRC/.. ; do
+        if [ -r "$ii/ShellScaffold.sh" ] ; then
+            . $ii/ShellScaffold.sh
+            break
+        fi
+    done
+}
+
+# You could replace this next line with the contents
+# of ShellScaffold.sh and this script will run just the same.
+mysetup
+
+runit
+pass