/**
* Adds the content pointed by the URL to the classpath during runtime. Uses reflection since
* <code>addURL</code> method of <code>URLClassLoader</code> is protected.
*/
public static void addUrlToClassPath(URL url, ClassLoader classLoader) {
try {
ReflectUtil.invokeDeclared(
URLClassLoader.class, classLoader, "addURL", new Class[] {URL.class}, new Object[] {url});
} catch (Exception ex) {
throw new IllegalArgumentException("Add URL failed: " + url, ex);
}
}
/**
* Finds and loads class on classpath even if it was already loaded.
*
* @param className class name to find
* @param classPath classpath
* @param parent optional parent class loader, may be <code>null</code>
*/
public static Class findClass(String className, URL[] classPath, ClassLoader parent) {
URLClassLoader tempClassLoader =
parent != null ? new URLClassLoader(classPath, parent) : new URLClassLoader(classPath);
try {
return (Class)
ReflectUtil.invokeDeclared(
URLClassLoader.class,
tempClassLoader,
"findClass",
new Class[] {String.class},
new Object[] {className});
} catch (Throwable th) {
throw new RuntimeException("Class not found: " + className, th);
}
}
/**
* Defines a class from byte array into the specified class loader. Warning: this is a
* <b>hack</b>!
*
* @param className optional class name, may be <code>null</code>
* @param classData bytecode data
* @param classLoader classloader that will load class
*/
public static Class defineClass(String className, byte[] classData, ClassLoader classLoader) {
try {
return (Class)
ReflectUtil.invokeDeclared(
ClassLoader.class,
classLoader,
"defineClass",
new Class[] {String.class, byte[].class, int.class, int.class},
new Object[] {
className, classData, Integer.valueOf(0), Integer.valueOf(classData.length)
});
} catch (Throwable th) {
throw new RuntimeException("Define class failed: " + className, th);
}
}