Casting to generic type in Java doesn't raise ClassCastException?
- by Kip
I have come across a strange behavior of Java that seems like a bug. Is it? Casting an Object to a generic type (say, K) does not throw a ClassCastException even if the object is not an instance of K. Here is an example:
import java.util.*;
public final class Test {
private static<K,V> void addToMap(Map<K,V> map, Object ... vals) {
for(int i = 0; i < vals.length; i += 2)
map.put((K)vals[i], (V)vals[i+1]); //Never throws ClassCastException!
}
public static void main(String[] args) {
Map<String,Integer> m = new HashMap<String,Integer>();
addToMap(m, "hello", "world"); //No exception
System.out.println(m.get("hello")); //Prints "world", which is NOT an Integer!!
}
}
