title: Error loading theme, cannot find "theme.css" resource of "primefaces-start" library
body: <p>When I run my project on Tomcat server, it shows this error:</p>
  
  <blockquote>
    <p>Error loading theme, cannot find "theme.css" resource of "primefaces-start" library</p>
  </blockquote>
  
  <p>Here's the stack trace:</p>
  
  <pre><code>javax.servlet.ServletException: Error loading theme, cannot find "theme.css" resource of "primefaces-start" library
      javax.faces.webapp.FacesServlet.service(FacesServlet.java:321)
      org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
  
  
  root cause 
  
  javax.faces.FacesException: Error loading theme, cannot find "theme.css" resource of "primefaces-start" library
      org.primefaces.renderkit.HeadRenderer.encodeTheme(HeadRenderer.java:130)
      org.primefaces.renderkit.HeadRenderer.encodeBegin(HeadRenderer.java:92)
      javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:824)
      javax.faces.component.UIComponent.encodeAll(UIComponent.java:1641)
      javax.faces.component.UIComponent.encodeAll(UIComponent.java:1646)
      com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:389)
      com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:127)
      com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:117)
      com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
      com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:135)
      javax.faces.webapp.FacesServlet.service(FacesServlet.java:309)
      org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
  </code></pre>
  
  <p>How is this caused and how can I solve it?</p>