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Java AbstractCollection类的isEmpty()方法

2024-04-24 02:48:03 401

isEmpty()AbstractCollection类的方法检查集合是否为空，即它是否具有零个元素。如果Collectionn没有元素，则返回。

语法如下-

public boolean isEmpty()

要使用Java中的AbstractCollection类，请导入以下包-

import java.util.AbstractCollection;

以下是isEmpty()在Java中实现AbstractCollection方法的示例-

示例

import java.util.ArrayList;
import java.util.AbstractCollection;

public class Demo {
   public static void main(String[] args) {
      AbstractCollection<Object> absCollection = new ArrayList<Object>();
      absCollection.add("Laptop");
      absCollection.add("Tablet");
      absCollection.add("Mobile");
      absCollection.add("E-Book Reader");
      absCollection.add("SSD");
      absCollection.add("HDD");
      System.out.println("AbstractCollection = " + absCollection);
      System.out.println("Collection is empty? = " + absCollection.isEmpty());
   }
}

输出结果

AbstractCollection = [Laptop, Tablet, Mobile, E-Book Reader, SSD, HDD]
Collection is empty? = false

让我们看另一个例子-

示例

import java.util.ArrayList;
import java.util.AbstractCollection;

public class Demo {
   public static void main(String[] args) {
      AbstractCollection<Object> absCollection = new ArrayList<Object>();
      System.out.println("AbstractCollection = " + absCollection);
      System.out.println("Collection is empty? = " + absCollection.isEmpty());
   }
}

输出结果

AbstractCollection = []
Collection is empty? = true

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Java AbstractCollection类的isEmpty()方法

示例

示例

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