When loading of FXML file fails, in some cases the error is not shown to the user

app/src/main/java/com/oracle/javafx/scenebuilder/app/SceneBuilderApp.java

@@ -647,7 +647,7 @@ private void performOpenFiles(List<File> fxmlFiles,
         assert fxmlFiles != null;
         assert fxmlFiles.isEmpty() == false;
 
-        final Map<File, IOException> exceptions = new HashMap<>();
+        final Map<File, Exception> exceptions = new HashMap<>();
         for (File fxmlFile : fxmlFiles) {
             try {
                 final DocumentWindowController dwc
@@ -668,7 +668,7 @@ private void performOpenFiles(List<File> fxmlFiles,
                     hostWindow.loadFromFile(fxmlFile);
                     hostWindow.openWindow();
                 }
-            } catch (IOException xx) {
+            } catch (RuntimeException | IOException xx) {
                 exceptions.put(fxmlFile, xx);
             }
         }

kit/src/main/java/com/oracle/javafx/scenebuilder/kit/fxom/FXOMLoader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 Gluon and/or its affiliates.
+ * Copyright (c) 2017, 2021, Gluon and/or its affiliates.
  * Copyright (c) 2012, 2014, Oracle and/or its affiliates.
  * All rights reserved. Use is subject to license terms.
  *
@@ -95,10 +95,27 @@ public void load(String fxmlText) throws java.io.IOException {
             is.reset();
             setSceneGraphRoot(fxmlLoader.load(is));
         } catch (RuntimeException | IOException x) {
-            if (x.getCause().getClass() == XMLStreamException.class) {
-                handleUnsupportedCharset(x);
-            } else
-                throw new IOException(x);
+            handleFxmlLoadingError(x);
+        }
+    }
+
+    private void handleFxmlLoadingError(Exception x) throws IOException {
+        if (x.getCause() != null) {
+            handleKnownCauses(x);
+        } else {
+            handleUnknownAndMissingCauses(x);
+        }
+    }
+
+    private void handleUnknownAndMissingCauses(Exception x) throws IOException {
+        throw new IOException(x);
+    }
+
+    private void handleKnownCauses(Exception x) throws IOException {
+        if (x.getCause().getClass() == XMLStreamException.class) {
+            handleUnsupportedCharset(x);
+        } else {                    
+            handleUnknownAndMissingCauses(x);
         }
     }
 

kit/src/test/java/com/oracle/javafx/scenebuilder/kit/fxom/FXOMDocumentTest.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2021, Gluon and/or its affiliates.
+ * All rights reserved. Use is subject to license terms.
+ *
+ * This file is available and licensed under the following license:
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  - Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  - Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the distribution.
+ *  - Neither the name of Oracle Corporation and Gluon nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.oracle.javafx.scenebuilder.kit.fxom;
+
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.net.URL;
+
+import org.junit.Test;
+
+public class FXOMDocumentTest {
+    @Test
+    public void that_IOexception_is_thrown_in_case_FXMLLoader_error() throws Exception {
+        URL resource = getClass().getResource("BrokenByUserData.fxml");
+        String fxmlText = FXOMDocument.readContentFromURL(resource);
+        Throwable t = assertThrows(IOException.class, () -> new FXOMDocument(fxmlText, resource, null, null));
+        String message = t.getMessage();
+        assertTrue(message.startsWith("javafx.fxml.LoadException:"));
+    }
+}

kit/src/test/resources/com/oracle/javafx/scenebuilder/kit/fxom/BrokenByUserData.fxml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.Button?>
+<?import javafx.scene.control.TableColumn?>
+<?import javafx.scene.control.TableView?>
+<?import javafx.scene.layout.HBox?>
+<?import javafx.scene.layout.VBox?>
+
+<VBox prefWidth="940.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="io.a2l.extenso.kitdev.controllers.MethodFilesController">
+    <userData>
+        <fx:reference source="controller"/>
+    </userData>
+   <children>
+      <HBox spacing="7.0">
+         <children>
+            <Button fx:id="importButton" mnemonicParsing="false" onAction="#onImport" text="Import methods" />
+            <Button fx:id="exportButton" mnemonicParsing="false" onAction="#onExport" text="Export selection" />
+            <Button fx:id="analysisButton" mnemonicParsing="false" onAction="#onAnalysis" text="Use method for analysis" />
+            <Button fx:id="deleteButton" mnemonicParsing="false" onAction="#onDelete" text="Delete selected methods" />
+         </children>
+         <opaqueInsets>
+            <Insets />
+         </opaqueInsets>
+         <padding>
+            <Insets bottom="7.0" left="7.0" right="7.0" top="7.0" />
+         </padding>
+      </HBox>
+      <TableView fx:id="tableView" minWidth="700.0" VBox.vgrow="ALWAYS">
+        <columns>
+          <TableColumn fx:id="kitId" editable="false" prefWidth="178.0" text="Kit ID" />
+          <TableColumn fx:id="methodId" editable="false" prefWidth="164.0" text="Method ID" />
+          <TableColumn fx:id="revision" editable="false" prefWidth="148.0" text="Revision" />
+        </columns>
+      </TableView>
+   </children>
+</VBox>