Sample .project file in eclipse to add facets when not it's not added before

project.xml

<projectDescription>
  <name>myproject</name>
  <buildSpec>
    <buildCommand>
      <name>org.eclipse.jdt.core.javabuilder</name>
      <arguments></arguments>
    </buildCommand>
    <buildCommand>
      <name>org.eclipse.jdt.core.javabuilder</name>
      <arguments></arguments>
    </buildCommand>
  </buildSpec>
  <natures>
    ...
    <nature>org.eclipse.wst.common.project.facet.core.nature</nature>
    ...
  </natures>
</projectDescription>