6858708: HotspotDiagnosticMXBean.setVMOption() throws NullPointerException

Add a null check for the VM option string

Reviewed-by: mchung, ohair
diff --git a/jdk/src/share/classes/sun/management/Flag.java b/jdk/src/share/classes/sun/management/Flag.java
index 0fed5c1..44b4139 100644
--- a/jdk/src/share/classes/sun/management/Flag.java
+++ b/jdk/src/share/classes/sun/management/Flag.java
@@ -45,7 +45,7 @@
     Flag(String name, Object value, boolean writeable,
          boolean external, Origin origin) {
         this.name = name;
-        this.value = value;
+        this.value = value == null ? "" : value ;
         this.origin = origin;
         this.writeable = writeable;
         this.external = external;
@@ -64,8 +64,7 @@
     }
 
     VMOption getVMOption() {
-        String val = value == null ? "" : value.toString();
-        return new VMOption(name, val, writeable, origin);
+        return new VMOption(name, value.toString(), writeable, origin);
     }
 
     static Flag getFlag(String name) {
diff --git a/jdk/test/com/sun/management/HotSpotDiagnosticMXBean/SetAllVMOptions.java b/jdk/test/com/sun/management/HotSpotDiagnosticMXBean/SetAllVMOptions.java
new file mode 100644
index 0000000..8f19de2
--- /dev/null
+++ b/jdk/test/com/sun/management/HotSpotDiagnosticMXBean/SetAllVMOptions.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2005-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug     6858708
+ * @summary Basic Test for HotSpotDiagnosticMXBean.setVMOption()
+ * @author  Tomas Hurka, Daniel Fuchs
+ *
+ * @run main SetAllVMOptions
+ */
+
+import com.sun.management.HotSpotDiagnosticMXBean;
+import com.sun.management.VMOption;
+import java.lang.management.ManagementFactory;
+import java.util.List;
+import javax.management.MBeanServer;
+
+public class SetAllVMOptions {
+    private static String HOTSPOT_DIAGNOSTIC_MXBEAN_NAME =
+        "com.sun.management:type=HotSpotDiagnostic";
+
+    public static void main(String[] args) throws Exception {
+        List<HotSpotDiagnosticMXBean> list =
+            ManagementFactory.getPlatformMXBeans(HotSpotDiagnosticMXBean.class);
+        HotSpotDiagnosticMXBean mbean = list.get(0);
+        setAllVMOptions(mbean);
+
+        MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
+        mbean = ManagementFactory.newPlatformMXBeanProxy(mbs,
+                    HOTSPOT_DIAGNOSTIC_MXBEAN_NAME,
+                    HotSpotDiagnosticMXBean.class);
+        setAllVMOptions(mbean);
+    }
+
+    private static void setAllVMOptions(HotSpotDiagnosticMXBean mbean) {
+        List<VMOption> options = mbean.getDiagnosticOptions();
+        for (VMOption opt : options) {
+            String name = opt.getName();
+            String val = opt.getValue();
+            System.out.println("option: "+name+"="+val);
+            mbean.setVMOption(name,val);
+        }
+    }
+}