package org.kodejava.basic;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class TypeSpecificCollection {
public static void main(String[] args) {
// Using a Generic can enable us to create a type specific collection
// object. In the example below we create a Map whose key is an Integer
// a have the value of a String.
Map<Integer, String> grades = new HashMap<>();
grades.put(1, "A");
grades.put(2, "B");
grades.put(3, "C");
grades.put(4, "D");
grades.put(5, "E");
// A value obtained from type specific collection doesn't need to
// be cast, it knows the type returned.
String value = grades.get(1);
System.out.println("value = " + value);
// Creating a List that will contain a String only values.
List<String> dayNames = new ArrayList<>();
dayNames.add("Sunday");
dayNames.add("Monday");
dayNames.add("Tuesday");
dayNames.add("Wednesday");
// We also don't need to cast the retrieved value because it knows the
// returned type object.
String firstDay = dayNames.get(0);
System.out.println("firstDay = " + firstDay);
}
}
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