Java documentation interpretation: Detailed explanation of the usage of the isEmpty() method of the HashSet class

Interpretation of Java documentation: Detailed explanation of the usage of the isEmpty() method of the HashSet class, specific code examples are required

The HashSet class in the Java collection framework is a method used to store A data structure with sequential and non-repeating elements. In practical applications, we often need to determine whether a HashSet object is empty. At this time, you can use the isEmpty() method of the HashSet class to judge.

isEmpty() method is defined as follows:

public boolean isEmpty()

isEmpty() method returns a boolean value indicating whether the current HashSet object is empty. If there are no elements in the HashSet object, return true; if there are elements in the HashSet object, return false.

The following uses specific code examples to illustrate the specific usage of the isEmpty() method.

import java.util.HashSet;

public class HashSetExample {
    public static void main(String[] args) {
        // 创建一个空的HashSet对象
        HashSet<String> set1 = new HashSet<>();

        // isEmpty()方法示例1
        System.out.println("isEmpty()方法示例1：");
        System.out.println("set1是否为空：" + set1.isEmpty()); // 输出true

        // 添加元素到HashSet对象中
        set1.add("apple");
        set1.add("banana");
        set1.add("orange");

        // isEmpty()方法示例2
        System.out.println("isEmpty()方法示例2：");
        System.out.println("set1是否为空：" + set1.isEmpty()); // 输出false

        // 创建一个非空的HashSet对象
        HashSet<Integer> set2 = new HashSet<>();
        set2.add(1);
        set2.add(2);
        set2.add(3);

        // isEmpty()方法示例3
        System.out.println("isEmpty()方法示例3：");
        System.out.println("set2是否为空：" + set2.isEmpty()); // 输出false

        // 清空HashSet对象中的元素
        set2.clear();

        // isEmpty()方法示例4
        System.out.println("isEmpty()方法示例4：");
        System.out.println("set2是否为空：" + set2.isEmpty()); // 输出true
    }
}

The above code example creates two HashSet objects: set1 and set2. First, we created an empty HashSet object set1 and used the isEmpty() method to determine whether it was empty and returned true.

Next, we added three elements to set1, and then used the isEmpty() method again to determine whether set1 was empty and returned false.

Next, we created a non-empty HashSet object set2 and used the isEmpty() method to determine whether it was empty and returned false.

Finally, we cleared the elements in set2 through the clear() method, and then used the isEmpty() method again to determine whether set2 was empty and returned true.

The above code example clearly shows the specific usage of the isEmpty() method of the HashSet class when determining whether the HashSet object is empty.

In actual development, we often need to use the isEmpty() method to determine whether the HashSet object is empty, so as to handle it accordingly according to the specific situation. After mastering the usage of the isEmpty() method, we can operate the HashSet object more flexibly and improve the readability and maintainability of the code.

Summary: The isEmpty() method of the HashSet class is used to determine whether the HashSet object is empty. According to the return value of the isEmpty() method, we can determine whether the HashSet object contains elements and perform corresponding processing according to the specific situation.

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