SCJP Module-9 Question-9
The program given below will check your understanding NavigableSet, List, ArrayList and TreeSet of collection framework in Java.
The program given below will check your understanding NavigableSet, List, ArrayList and TreeSet of collection framework in Java.Given below the sample code :
public class Check{
public static void main(String args[]){
ArrayList alist = new ArrayList();
ArrayList<String> listStr = alist;
ArrayList<StringBuffer> listBuf = alist;
listStr.add(0, "Welcome");
StringBuffer buff = listBuf.get(0);
System.out.println(buff.toString());
}
}
What will be the output of the following?
1. Welcome
2. Compile error
3. java.lang.ClassCastException
4. null
Answer
(3)
Explanation
'java.lang.String' cannot be cast to 'java.lang.StringBuffer'
