io.keikai.importer.ImportException: Fail to import drawing in sheet Sheet1 from book importError.xlsx
	at io.keikai.importer.XlsxImporter.imports(XlsxImporter.java:300)
	at io.keikai.range.impl.imexp.ExcelImportAdapter.imports(ExcelImportAdapter.java:48)
	at io.keikai.range.impl.imexp.AbstractImporter.imports(AbstractImporter.java:57)
	at io.keikai.ui.Spreadsheet.getSBook(Spreadsheet.java:634)
	at io.keikai.ui.Spreadsheet.getSelectedSSheet(Spreadsheet.java:813)
	at io.keikai.ui.Spreadsheet.doInvalidate(Spreadsheet.java:2494)
	at io.keikai.ui.Spreadsheet.invalidate(Spreadsheet.java:2351)
	at io.keikai.ui.Spreadsheet.setSrc(Spreadsheet.java:853)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.zkoss.zk.ui.metainfo.Property.assign0(Property.java:332)
	at org.zkoss.zk.ui.metainfo.Property.assign(Property.java:174)
	at org.zkoss.zk.ui.metainfo.ComponentInfo.applyProperties(ComponentInfo.java:742)
	at org.zkoss.zk.ui.impl.AbstractUiFactory.newComponent(AbstractUiFactory.java:146)
	at org.zkoss.zk.ui.impl.UiEngineImpl.execCreateChild0(UiEngineImpl.java:924)
	at org.zkoss.zk.ui.impl.UiEngineImpl.execCreateChild(UiEngineImpl.java:894)
	at org.zkoss.zk.ui.impl.UiEngineImpl.execCreate0(UiEngineImpl.java:781)
	at org.zkoss.zk.ui.impl.UiEngineImpl.execCreate(UiEngineImpl.java:745)
	at org.zkoss.zk.ui.impl.UiEngineImpl.execNewPage0(UiEngineImpl.java:466)
	at org.zkoss.zk.ui.impl.UiEngineImpl.execNewPage(UiEngineImpl.java:374)
	at org.zkoss.zk.ui.http.DHtmlLayoutServlet.process(DHtmlLayoutServlet.java:215)
	at org.zkoss.zk.ui.http.DHtmlLayoutServlet.doGet(DHtmlLayoutServlet.java:140)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder$NotAsyncServlet.service(ServletHolder.java:1386)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:755)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:547)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:590)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1610)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1300)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1580)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1215)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:221)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
	at org.eclipse.jetty.server.Server.handle(Server.java:500)
	at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383)
	at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:547)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:273)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:375)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.NullPointerException
	at io.keikai.importer.XlsxExtractor$XlsxDrawingsExtractor.getDrawingsJson(XlsxExtractor.java:2921)
	at io.keikai.importer.XlsxImporter.importDrawings(XlsxImporter.java:807)
	at io.keikai.importer.XlsxImporter.imports(XlsxImporter.java:281)
	... 60 more