How to use @SuppressWarning("unchecked") to specific lines of code and not into method level

Question

I have a function created where i have used @SuppressWarning("unchecked") at method level and it works as expected but i need to move this @SuppressWarning("unchecked") to only those lines of code where the warning is coming in and not at method level:

public static <T> T marshal(Class<T> cls , String xml){
      T res;
      if(cls == xml.getClass()){
          res=(T) xml;--->Need to use @SuppressWarning("unchecked") before this line
      }else{
         JAXBContext ct= JAXBContext.newInstance(cls);
         Unmarshal marshal=ctx.createUnmarshller();
         res=(T)marshal.unmarshal(new StringReader(xml));-->Need to use @SuppressWarning("unchecked") before this line
      }
      return res;
     }

In the above function I have to use @SuppressWarning("unchecked") after if and else because these are the places where warnings are shown.

Answer 1

You could use a generic method to handle @SuppressWarning("unchecked") when appropriate, so defined like:

@SuppressWarnings("unchecked")
public <C> C cast(Object o) {
    return (C) o;
}

However, when you use it and want to have checks you need to check for possible ClassCastException upon assignment (see this). So like:

try {
    res = cast(xml);
} catch (ClassCastException cce) {
    // a bug, help!
}