36 lines
1005 B
Java
36 lines
1005 B
Java
|
//: containers/ApplesAndOrangesWithoutGenerics.java
|
|||
|
|
// <20>2015 MindView LLC: see Copyright.txt
|
|||
|
|
// Simple container use (suppressing compiler warnings)
|
|||
|
|
// {ThrowsException}
|
|||
|
|
import java.util.*;
|
|||
|
|
|
|||
|
|
class Apple {
|
|||
|
|
private static long counter;
|
|||
|
|
private final long id = counter++;
|
|||
|
|
public long id() { return id; }
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
class Orange {}
|
|||
|
|
|
|||
|
|
public class ApplesAndOrangesWithoutGenerics {
|
|||
|
|
@SuppressWarnings("unchecked")
|
|||
|
|
public static void main(String[] args) {
|
|||
|
|
ArrayList apples = new ArrayList();
|
|||
|
|
for(int i = 0; i < 3; i++)
|
|||
|
|
apples.add(new Apple());
|
|||
|
|
// Not prevented from adding an Orange to apples:
|
|||
|
|
apples.add(new Orange());
|
|||
|
|
for(Object apple : apples) {
|
|||
|
|
((Apple) apple).id();
|
|||
|
|
// Orange is detected only at run time
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
} /* Output:
|
|||
|
|
___[ Error Output ]___
|
|||
|
|
Exception in thread "main" java.lang.ClassCastException:
|
|||
|
|
Orange cannot be cast to Apple
|
|||
|
|
at ApplesAndOrangesWithoutGenerics.main(ApplesAndOr
|
|||
|
|
angesWithoutGenerics.java:23)
|
|||
|
|
___[ Exception is Expected ]___
|
|||
|
|
*///:~
|