Primefaces page layout with tree menu as navigation
<p:layoutUnit position="west" size="200" header="Left"
            resizable="true" collapsible="true">
            <h:form>
                <p:tree dynamic="true" value="#{treeBean.root}" var="node" id="tree"
                    selectionMode="single">
                    <p:treeNode id="treeNode">
                        <h:outputText value="#{node}" id="lblNode" />
                    </p:treeNode>
                </p:tree>
            </h:form>
        </p:layoutUnit>

root = new DefaultTreeNode("Root", null);
        TreeNode node0 = new DefaultTreeNode("Color", root);


        TreeNode node00 = new DefaultTreeNode("Red", node0);
        TreeNode node01 = new DefaultTreeNode("Blue", node0);
        TreeNode node02 = new DefaultTreeNode("Green", node0);

public void onNodeSelect(NodeSelectEvent event) {

        try {
            System.out.println(" here " + event.getTreeNode().getData());
            FacesContext
                    .getCurrentInstance()
                    .getApplication()
                    .getNavigationHandler()
                    .handleNavigation(FacesContext.getCurrentInstance(),
                            "null", "/start.xhtml?faces-redirect=true");
        } catch (Exception e) {
            logger.info("error "+e.getMessage());
            // TODO: handle exception
        }

<p:layout>
        <p:layoutUnit position="east" header="Menu"  collapsed="true" scrollable="true" collapsible="true" >
            <ui:insert name="appMenu">
                Place Your menu here ...
            </ui:insert>
        </p:layoutUnit>

        <p:layoutUnit position="center" scrollable="true">
            <ui:insert name="pageContent">
                Page Content is loaded here .....
            </ui:insert>
        </p:layoutUnit>
    </p:layout>

<ui:composition template="myLayoutTemplate.xhtml">
    <ui:define name="pageContent">

    </ui:define>
</ui:composition>