package java_list; import java.util.ArrayList; import java.util.Collections; import java.util.Date; import java.util.List; /** * @web http://java-buddy.blogspot.com/ */ public class Java_List { public static void main(String[] args) { //List with type specified List<String> list1 = new ArrayList<String>(); list1.add("ABC"); //list1.add(123); //list1.add(12345.678); //list1.add(new Date()); /* compile time error: * - no suitable method found for add(int) * - no suitable method found for add(double) * - no suitable method found for add(Date) */ //List without type specified List list2 = new ArrayList(); list2.add("ABC"); list2.add(123); list2.add(12345.678); list2.add(new Date()); for(int i = 0; i < list2.size(); i++){ System.out.println( list2.get(i).getClass().getName() + " : " + list2.get(i)); } //List without type specified //Returns a dynamically typesafe view with Collections.checkedList() List list3 = new ArrayList(); list3 = Collections.checkedList(list3, String.class); list3.add("ABC"); //list3.add(123); //list3.add(12345.678); //list3.add(new Date()); /* runtime error: * java.lang.ClassCastException: Attempt to insert class * java.lang.Integer/Double/Date element into collection with element * type class java.lang.String */ } }
Tuesday, October 1, 2013
Example of inserting data of different type to List
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