jetbrick-commons/src/main/java/jetbrick/beans/ClassLoaderUtils.java
public static Class<?> loadClass(final String qualifiedClassName, ClassLoader loader) {
        try {
            return loadClassEx(qualifiedClassName, loader);
        } catch (ClassNotFoundException e) {
            return null;
        }
    }
public static Class<?> loadClass(final String qualifiedClassName, ClassLoader loader) {
        try {
            return loadClassEx(qualifiedClassName, loader);
        } catch (ClassNotFoundException e) {
            return null;
        }
    }
使用默认的 ClassLoader 去载入类.
@return null if class not found