When contents of WebView are printed, the following exception is thrown several times:

java.lang.ClassCastException: com.sun.prism.d3d.D3DRTTexture cannot be cast to com.sun.prism.j2d.J2DRTTexture
at com.sun.prism.j2d.J2DPrismGraphics.drawPixelsMasked(J2DPrismGraphics.java:1065)
at com.sun.javafx.webkit.prism.WCGraphicsPrismContext$ClipLayer.render(WCGraphicsPrismContext.java:1260)
at com.sun.javafx.webkit.prism.WCGraphicsPrismContext.renderLayer(WCGraphicsPrismContext.java:158)
at com.sun.javafx.webkit.prism.WCGraphicsPrismContext.restoreStateInternal(WCGraphicsPrismContext.java:176)
at com.sun.javafx.webkit.prism.WCGraphicsPrismContext.restoreState(WCGraphicsPrismContext.java:189)
at com.sun.webkit.graphics.GraphicsDecoder.decode(GraphicsDecoder.java:202)
at com.sun.webkit.graphics.WCRenderQueue.decode(WCRenderQueue.java:69)
at com.sun.webkit.WebPage.print(WebPage.java:1780)
at javafx.scene.web.WebEngine$Printable$Peer.renderContent(WebEngine.java:1373)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:1598)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1517)
at com.sun.prism.j2d.print.J2DPrinterJob$J2DPageable.printNode(J2DPrinterJob.java:981)
at com.sun.prism.j2d.print.J2DPrinterJob$J2DPageable.print(J2DPrinterJob.java:971)
at sun.print.RasterPrinterJob.printPage(RasterPrinterJob.java:2037)
at sun.print.RasterPrinterJob.print(RasterPrinterJob.java:1485)
at com.sun.prism.j2d.print.J2DPrinterJob$PrintJobRunnable.run(J2DPrinterJob.java:714)
at java.lang.Thread.run(Thread.java:724)

Then, debug messages start being printed:

D3D Vram Pool: 13 645 258 used (5,1%), 13 645 258 managed (5,1%), 268 435 456 total
J2D Texture Pool: 98 304 used (0,0%), 98 304 managed (0,0%), 268 435 456 total
70 total resources being managed
6 permanent resources (8.6%)
5 resources locked (7.1%)
37 resources contain interesting data (52.9%)
0 resources disappeared (0.0%)