JAXB Marshaller no threadsafe - Error

I got this error...

java.lang.ArrayIndexOutOfBoundsException: -1

at com.sun.xml.bind.v2.util.CollisionCheckStack.pushNocheck(CollisionCheckStack.java:132)

at com.sun.xml.bind.v2.runtime.XMLSerializer.childAsRoot(XMLSerializer.java:491)

at com.sun.xml.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:323)

at com.sun.xml.bind.v2.runtime.MarshallerImpl.marshal(MarshallerImpl.java:251)

at javax.xml.bind.helpers.AbstractMarshallerImpl.marshal(AbstractMarshallerImpl.java:116)

at ....sci.XmlUtil.convertToXml(XmlUtil.java:52)

or this one:

java.lang.NullPointerException

at com.sun.xml.internal.bind.v2.runtime.Coordinator.popCoordinator(Coordinator.java:150)

at com.sun.xml.internal.bind.v2.runtime.XMLSerializer.close(XMLSerializer.java:847)

at com.sun.xml.internal.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:317)

at com.sun.xml.internal.bind.v2.runtime.MarshallerImpl.marshal(MarshallerImpl.java:236)

at javax.xml.bind.helpers.AbstractMarshallerImpl.marshal(AbstractMarshallerImpl.java:116)

at .....XmlUtil.convertToXml(XmlUtil.java:52)

Cause:

Our XML class was sharing Marshaller and Unmarshaller instances among several threads.

Solution:

Create a Marshaller and Unmarshaller per request, as described in this Link