Java Examples - Collection Length
Java ExamplesThe following example demonstrates how to use the collection.add() method of the Collections class to add data and use collection.size() to calculate the length of the collection:
Main.java file
import java.util.*;
public class Main {
public static void main(String [] args) {
System.out.println( "Collection instance!\n" );
int size;
HashSet collection = new HashSet ();
String str1 = "Yellow", str2 = "White", str3 =
"Green", str4 = "Blue";
Iterator iterator;
collection.add(str1);
collection.add(str2);
collection.add(str3);
collection.add(str4);
System.out.print("Collection data:");
iterator = collection.iterator();
while (iterator.hasNext()){
System.out.print(iterator.next() + " ");
}
System.out.println();
size = collection.size();
if (collection.isEmpty()){
System.out.println("The collection is empty");
}
else{
System.out.println( "Collection length:" + size);
}
System.out.println();
}
}
The output of running the above code is:
集合实例! 集合数据: White Yellow Blue Green 集合长度: 4Other Extensions