[libvirt] getSchedulerParameters() always returning nullpointerexception in JAVA

Frederic Dang Tran frederic.dangtran at orange-ftgroup.com
Thu Dec 17 23:23:15 UTC 2009


Hi,
I came across the same problem: Domain.getSchedulerParameters()  throws a NullPointerException systematically.

  
getSchedulerParameters
The culprit is the org.libvirt.jna.virSchedParameterValue class which should inherit from jna.Union instead of Structure:
	public class virSchedParameterValue extends Union { 
	...
 	} 

Regards,
Frederic


On 12/14/2009 04:22 AM, Marc Gonzalez Mateo wrote:
OK, let's see if Bryan has an idea/solution about this.

Thanks guys!



MARC


El 11/12/2009, a las 14:29, Daniel Veillard escribió:

On Fri, Dec 11, 2009 at 02:01:36PM +0100, Marc Gonzalez Mateo wrote:
Hi everyvody,
I'm developing a new API based on libvirt.
I'm currently stucked using getSchedulerParameters, always is returning a
nullpointerexception, no matter which Xen Domain I'm passing to the
function.

Enclosing both the code and the error console:


public int getCPUPriority(String name) {
        int res=-1;

        try {
            Domain d = getDomain(name);
            SchedParameter[] pars = d.getSchedulerParameters();
  Hum, it seems

    Domain.getSchedulerParameters()

does

    SchedParameter[] returnValue = new SchedParameter[0];

and

        public static SchedParameter create(virSchedParameter vParam) {
            SchedParameter returnValue = null;
            switch (vParam.type) {
                case (1):

and the create method getting there gets a null pointer as the
initialization argument, which it first dereference ...

  so not surprizing looking at the code, maybe Bryan has an idea of what
is going on there, I'm a bit lost in this initialization process ...

Daniel

            for (SchedParameter pri : pars) {
                if (pri.field=="weight")
                    res=Integer.parseInt(pri.getValueAsString());
            }

        } catch (LibvirtException e) {
            log.error(" Error: getting CPU priority of \""+name+"\"." +
e.getClass());
            e.printStackTrace();
        }

        return res;
    }



Dec 11, 2009 1:04:18 PM net.emotivecloud.virtmonitor.VirtMonitor
getCPUCapacity
SEVERE:  Error: getting CPU capacity of "XenTest".
java.lang.NullPointerException
    at org.libvirt.SchedParameter.create(Unknown Source)
    at org.libvirt.Domain.getSchedulerParameters(Unknown Source)
    at
net.emotivecloud.virtmonitor.VirtMonitor.getCPUCapacity(VirtMonitor.java:462)
    at net.emotivecloud.virtmonitor.VirtMonitor.main(VirtMonitor.java:763)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:283)
    at java.lang.Thread.run(Thread.java:636)


Any ideas?

Thanks in advance,


Marc Gonzalez Mateo
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Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
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Frederic Dang Tran



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