当数组长度为0时,isEmpty()方法返回true;否则,返回false。 实际上,在Java中我们无法直接检查一个数组是否为空。但我们可以通过判断数组的长度来间接判断数组是否为空,这就是isEmpty()方法的原理。 示例: int[]arr1=newint[3];int[]arr2=newint[0];System.out.println(arr1.length==0);// 输出 falseSyst...
AI代码解释 /**<p>NOTE:This method changedinLang version2.0.*It no longer trims the CharSequence.*That functionality is availableinisBlank().</p>**@param cs the CharSequence to check,may benull*@return{@codetrue}ifthe CharSequence is empty ornull*@since3.0Changed signature fromisEmpty(Stri...
下面是这种情况的示例代码: importjava.util.Objects;publicclassdemo{publicstaticvoidmain(String[]args){Stringstr=null;// 使用Objects.isNull()方法判定字符串引用是否为nullif(Objects.isNull(str)||str.isEmpty()){System.out.println("字符串str是空串或null");}}} Java Copy 最后,当我们需要在Map中判...
ConcurrentLinkedQueue源码 /*** Returns {@codetrue} if this queue contains no elements. * *@return{@codetrue} if this queue contains no elements*/publicbooleanisEmpty() {returnfirst() ==null; }/*** Returns the number of elements in this queue. If this queue * contains more than {@cod...
* That functionality is availableinisBlank().</p> * * @param cs the CharSequence to check, may be null * @return{@codetrue}ifthe CharSequence is empty or null * @since 3.0 Changed signature from isEmpty(String) to isEmpty...
java.util.Set.isEmpty()方法用于检查集合是否为空。如果集合为空,则返回真,否则返回假。语法:boolean isEmpty() 参数:该方法不取任何参数返回值:如果集合为空,方法返回真,否则返回假。下面的程序说明了 java.util.Set.isEmpty()方法:// Java code to illustrate isEmpty() import java.io.*; import java....
* That functionality is available in isBlank().</p> * *@paramcs the CharSequence to check, may be null *@return{@codetrue} if the CharSequence is empty or null *@since3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence) ...
* * <p>NOTE: This method changedinLang version 2.0. * It no longer trims the CharSequence. * That functionality is availableinisBlank().</p> * * @param cs the CharSequence to check, may be null * @return{@codetrue}ifthe CharSequence is empty or null * @since 3.0 Changed signature...
is designed to handle scenarios where a value may be present or absent, avoiding the need for null checks. TheisPresentandisEmptymethods are used to check the presence or absence of a value within anOptionalobject. In this article, we will explore the usage of these methods with code ...
// Java code to show the implementation of // isEmpty method in Map interface import java.util.*; public class GfG { // Driver code public static void main(String[] args) { // Initializing a Map of type HashMap Map<String, String> map = new HashMap<>(); System.out.println(map)...