Unable to import GraphML (.gml) file for preview

[SOUMAJYOTI]

I tried to call the PreviewJFrame script in https://github.com/gephi/gephi-toolkit-demos/blob/master/src/main/java/org/gephi/toolkit/demos/PreviewJFrame.java

directly using the below .gml file, but on executing, it shows # Nodes loaded:0 # Edges loaded: 0, when actually my toy file contains 1 node as can be seen.

I have attached the .gml file for reproducing here below:

<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
<graph id="G" edgedefault="directed">
<node id="n0" labels=":Host"><data key="labels">:Host</data><data key="portName">H1</data><data key="maxInDeg">0</data><data key="available">0</data><data key="maxOutDeg">0</data></node>
</graph>
</graphml>