| java.util.concurrent.Callable<V> | 
A task that returns a result and may throw an exception. Implementors define a single method with no arguments called call.
The Callable interface is similar to Runnable, in that both are designed for classes whose
 instances are potentially executed by another thread.  A
 Runnable, however, does not return a result and cannot
 throw a checked exception.
 
 The Executors class contains utility methods to
 convert from other common forms to Callable classes.
| Public Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Computes a result, or throws an exception if unable to do so. | |||||||||||
Computes a result, or throws an exception if unable to do so.
| Exception | if unable to compute a result | 
|---|