import java.util.Collections;
import java.util.Hashtable;
import java.util.Map;
public class MainClass {
public static void main(String[] s) {
Hashtable table = new Hashtable();
table.put("key1", "value1");
table.put("key2", "value2");
table.put("key3", "value3");
Map m = Collections.unmodifiableMap(table);
m.put("key3", "value3");
System.out.println(m);
}
}
Exception in thread "main" java.lang.UnsupportedOperationException
at java.util.Collections$UnmodifiableMap.put(Collections.java:1286)
at MainClass.main(MainClass.java:14)