I ended up using PMD. Code example can be seen below:
final Java15Parser parser = new Java15Parser();
final FileInputStream stream = new FileInputStream("VehicleServiceType.java");
final Object c = parser.parse(new InputStreamReader(stream));
final XPath xpath = new BaseXPath("//TypeDeclaration/Annotation/NormalAnnotation[Name/@Image = 'WebService']",
new DocumentNavigator());
for (final Iterator iter = xpath.selectNodes(c).iterator(); iter.hasNext();) {
final Object obj = iter.next();
// Do code generation based on annotations...
}