Problems With DOM Parsing

Hello! I'm having problems with parsing my XML code. I'm using DOM (org.w3c.dom and javax.xml.parsers packages). I want to dynamically construct objects from XML documents, but I'm new to DOM and have very little experience with it. I've tried to filter out DOM-generated noise, I've tried putting the arguments to the <define/> tag both as attributes and as children; both of them have thrown me a NullPointerException. I'm extremely confused as to why this doesn't work, as it should work in my theory (might just be wishful thinking...). Below is my code.

Resources.java

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.SAXException;

@SuppressWarnings("unchecked")
public class Resources {
	private final Document document;
	private final DocumentBuilder builder;
	private final DocumentBuilderFactory builderFactory;
	private final Map<String, Class<?>> classMap = new HashMap<>();
	private final Map<String, Resource> resources = new HashMap<>();
	public final DecoderGroup decoderGroup = new DecoderGroup();
	public Resources(InputStream inputStream) throws ResourceException {
		try {
			this.builderFactory = DocumentBuilderFactory.newInstance();
			this.builder = this.builderFactory.newDocumentBuilder();
			this.document = this.builder.parse(inputStream);
			if(!this.document.getFirstChild().getNodeName().equals("resources")) {
				throw new ResourceException("Invalid top-level tag.");
			}
		} catch(ParserConfigurationException | SAXException | IOException exception) {
			throw new ResourceException(exception);
		}
	}
	
	public Resources(URL url) throws IOException, ResourceException {
		this(url.openStream());
	}
	
	public <E extends Resource> E getResource(String name) throws ResourceException {
		if(this.resources.containsKey(name))
			return (E) this.resources.get(name);
		else
			throw new ResourceException("Resource not loaded!");
	}
	
	public void loadResources(boolean silent) throws ResourceException {
		if(silent) {
			new Thread() {
				public void run() {
					try {
						loadResources(false);
					} catch(ResourceException exception) {
						exception.printStackTrace();
						throw new RuntimeException(exception);
					}
				}
			}.start();
		} else {
			if(this.document.getFirstChild().hasChildNodes()) {
				for(Node i : ResourceUtils.toList(this.document.getFirstChild().getChildNodes())) {
					if(i.getNodeName().equals("#text") ||
							i.getNodeValue() == null ||
							i.getNodeValue().equals("null")) {
						continue;
					} else if(i.getNodeName().equals("define")) {
						
					} else if(this.classMap.containsKey(i.getNodeName())) {
						String name = null;
						for(Node j : ResourceUtils.toList(i.getAttributes())) {
							if(j.getNodeName().equals("name")) {
								name = j.getNodeValue();
								break;
							}
						}
						
						this.resources.put(name, this.loadResource(i));
					} else {
						throw new ResourceException("Uknown error!");
					}
				}
			}
		}
	}
	
	public Resource loadResource(Node rootNode) throws ResourceException {		
		try {
			Class<?> resourceClass = this.classMap.get(rootNode.getNodeValue());
			Resource resource;
			resource = (Resource) resourceClass.newInstance();
			
			if(rootNode.hasChildNodes()) {
				for(Node node : ResourceUtils.toList(rootNode.getChildNodes())) {
					Field field = resourceClass.getField(node.getNodeName());
					if(!this.decoderGroup.containsKey(field.getType())) {
						if(node.hasChildNodes()) {
							field.set(resource, loadResource(node));
						} else {
							throw new ResourceException("Unable to parse node.");
						}
					}
					
					field.set(resource, 
					this.decoderGroup.get(field.getType()).decode(node.getNodeValue()));
				}
			}
			return resource;
		} catch(IllegalAccessException | InstantiationException | 
				NoSuchFieldException exception) {
			exception.printStackTrace();
			throw new ResourceException(exception);
		}
	}
}

ResourceTest.java

import java.io.FileInputStream;

public class ResourceTest implements Resource {
	public String yay;
	public static void main(String[] args) throws Exception {
		Resources resources = new Resources(new FileInputStream("test.xml"));
		resources.loadResources(false);
		ResourceTest resourceTest = (ResourceTest) resources.getResource("test");
		System.out.println(resourceTest.yay);
	}
}

test.xml

<resources>
 	<define name="ResourceTest" class="org.angl.resource.ResourceTest" />
 	<ResourceTest name="test">
 		<yay>"YAY!"</yay>
 	</ResourceTest>
</resources>