Java ScriptEngine fails for 'long' addition?

Question

I'm using the ScriptEngine to perform calculations specified in a String. I tried a simple program as below:

 public static void main(String[] args){
    ScriptEngineManager mgr = new ScriptEngineManager();
    ScriptEngine engine = mgr.getEngineByName("JavaScript");
    Float f;
    try {
        f = new Float(engine.eval("1340984972921+7200000").toString());
        System.out.println(f.longValue()+"");
    } catch (Exception e){}
  }

This gives the output of 1340992126976 but the correct answer is 1340992172921

This seems to work for reasonably large integers but fails for long values. I want them as long values because they are timestamps and I want to use them as such. Any ideas on what could make this work?

Thanks.

Answer 1

Try changing the data type from Float to Double. I think it's a precision problem.