Searches the vector backwards for the specified object, starting from the specified index,
and returns an index to it.
The object equality is tested using the Java java.lang.Object.equals() method.
Returns -1 if the object is not found.
Parameters:
v
Note: The null value passed in this parameter will cause an error.
obj
If this parameter is null, the function will seek the occurence of null element.
fromIndex
indexOf()
You may call this function in a method-like style:
v.lastIndexOf(obj,fromIndex)