java.NoClassDefF_java-自定义URLClassLoader,运行时出现NoClassDefF...

我创建了自己的URLClassLoader,并通过java.system.class.loader将其设置为系统类加载器.它已经初始化,并且一切正常,但是找不到我要加载的类.这是URLClassLoader：

public class LibraryLoader extends URLClassLoader

{

public LibraryLoader(ClassLoader classLoader)

{

super(new URL[0], classLoader);

}

synchronized public void addJarToClasspath(String jarName) throws MalformedURLException, ClassNotFoundException

{

File filePath = new File(jarName);

URI uriPath = filePath.toURI();

URL urlPath = uriPath.toURL();

System.out.println(filePath.exists());

System.out.println(urlPath.getFile());

addURL(urlPath);

}

}

我已确认该罐子存在,并且路径正确.这是我在程序中如何称呼它：

LibraryLoader loader = (LibraryLoader) ClassLoader.getSystemClassLoader();

loader.addJarToClasspath("swt.jar");

这是我得到的例外(第166行是指我尝试创建新Point的行：

Exception in thread "main" java.lang.NoClassDefFoundError: org/eclipse/swt/graphics/Point

at mp.MyProgram.loadArchitectureLibraries(MyProgram.java:116)

at mp.MyProgram.main(MyProgram.java:90)

Caused by: java.lang.ClassNotFoundException: org.eclipse.swt.graphics.Point

at java.net.URLClassLoader$1.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

... 2 more

我什至尝试像这样显式加载类：

Class.forName("org.eclipse.swt.graphics.Point", false, loader);

是什么原因造成的？它不应该“正常工作”吗？

更新：这是MyProgram中的重要代码

public class MyProgram

{

// ...

public static void main(String[] args)

{

loadArchitectureLibraries();

// ...

}

public static void loadArchitectureLibraries()

{

LibraryLoader loader = (LibraryLoader) ClassLoader.getSystemClassLoader();

String architecture = System.getProperty("os.arch");

try {

if (architecture.contains("64")) {

loader.addJarToClasspath("swt-3.6.1-win32-win32-x86_64.jar");

} else {

loader.addJarToClasspath("swt-3.6.1-win32-win32-x86.jar");

}

Class.forName("org.eclipse.swt.graphics.Point", false, loader);

org.eclipse.swt.graphics.Point pt = new org.eclipse.swt.graphics.Point(0, 0);

} catch (Exception exception) {

exception.printStackTrace();

System.out.println("Could not load SWT library");

System.exit(1);

}

}

}

更新2：这是一个SSCCE：http://nucleussystems.com/files/myprogram.zip.调用java -Djava.system.class.loader = mp.LibraryLoader -jar myprogram.jar.