ObservableList and StringProperty are not sorted in XML file

Question

I want to write / read an XML file through JAXB using Java 1.7. In my files I use StringProperty, ObservableList and SimpleObjectProperty. I have an xml adapter for each of these classes. When I try to sort the classes, I get only an empty empty XML file.

ModelDescriptorHelper (saves the list of projects and the marshal and unmarshall xml file)

@XmlRootElement public class ModelDescriptorHelper { private static ModelDescriptorHelper helper = new ModelDescriptorHelper(); private File file; @XmlTransient private ObservableList<Project> projects = FXCollections.observableArrayList(); private SimpleListProperty<Project> projectsProperty = new SimpleListProperty(this, "projects", projects); public ObservableList<project> getProjects() { return projectsProperty.get(); } public void setCreoViewProjects(ObservableList<CreoViewProject> creoViewProjects) { creoViewProjectsProperty.set(creoViewProjects); } public SimpleListProperty<CreoViewProject> creoViewProjectsProperty() { return creoViewProjectsProperty; } private ModelDescriptorHelper readData() { try { File file = this.file; helper = JAXB.unmarshal(file, ModelDescriptorHelper.class); helper.file = file; } catch (Exception ex) { } return helper; } public void saveData() { try { if (!file.exists()) { file.getParentFile().mkdirs(); } else { file.delete(); file.createNewFile(); } try (BufferedOutputStream bf = new BufferedOutputStream(new FileOutputStream(file, false))) { JAXB.marshal(this, bf); } } catch (Exception ex) { ex.printStackTrace(); } } @XmlTransient public File getFile() { return file; } public void setFile(File file) { this.file = file; readData(); } public static ModelDescriptorHelper getInstance(File file) { helper.setFile(file); return helper; } } 

Project Class:

 public class Project { private SimpleStringProperty wtContextName = new SimpleStringProperty(); private SimpleStringProperty projectName = new SimpleStringProperty(); public String getProjectName() { return projectName.get(); } public void setProjectName(String projectName) { this.projectName.set(projectName); } public StringProperty projectNameProperty() { return projectName; } public String getWtContextName() { return wtContextName.get(); } public void setWtContextName(String wtContextName) { this.wtContextName.set(wtContextName); } public StringProperty wtContextNameProperty() { return wtContextName; } } 

StringPropertyAdapter:

 public class SimpleStringPropertyAdatper extends XmlAdapter<String, SimpleStringProperty> { @Override public SimpleStringProperty unmarshal(String v) throws Exception { return new SimpleStringProperty(v); } @Override public String marshal(SimpleStringProperty v) throws Exception { if(null == v) { return null; } return v.get(); // Or whatever the correct method is } 

}

ObservableListAdatper:

 public class ObservableListAdatper<T> extends XmlAdapter<LinkedList<T>, ObservableList<T>> { @Override public ObservableList<T> unmarshal(LinkedList<T> v) throws Exception { return FXCollections.observableList(v); } @Override public LinkedList<T> marshal(ObservableList<T> v) throws Exception { LinkedList<T> list = new LinkedList(); list.addAll(v); return list; // Or whatever the correct method is } 

}

Package Information:

 @XmlJavaTypeAdapters({ @XmlJavaTypeAdapter(value=SimpleStringPropertyAdatper.class, type=String.class), @XmlJavaTypeAdapter(value=ObservableListAdatper.class, type=ObservableList.class)}) package org.project; import javafx.collections.ObservableList; import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter; import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapters; 

Create a project and save the data in xml:

 ModelDescriptorHelper helper = ModelDescriptorHelper.getInstance(new File ("/test/test.xml")); Project project = new Project(); project.setProjectName("Test Project"); helper.getProjects().add(project); helper.getProjects().add(project); helper.saveData(); 

Xml file after marshall:

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <ModelDescriptorHelper> <projects/> </ModelDescriptorHelper> 

When I debug it seems that the marshaller calls 2 times the ObservableListAdatper. 1 Time when the list has 2 projects, the second time is empty.

What am I wrong?