Is it OK to try/catch something just to check if an exception was thrown or not?

Is it a good way to try something useless just to see if a particular exception is thrown by this code ?
I want to do something when the exception is thrown, and nothing otherwise.

try {  
    new BigDecimal("some string"); // This do nothing because the instance is ignored  
} catch (NumberFormatException e) {  
    return false; // OK, the string wasn't a well-formed decimal  
}  
return true;

There is too many preconditions to test, and the constructor BigDecimal() is always checking them all, so this seem the simplest method.