本程序利用多线程模拟多个发卡人同时发卡，请在阅读程序的基础上完成填空（5个空）。public class TestIssueClimbingCard {public static void main(String[] args) {IssueClimbingCard staffA = new IssueClimbingCard();IssueClimbingCard staffB = new IssueClimbingCard();IssueClimbingCard staffC = new IssueClimbingCard();staffA.setName("发卡人A");staffB.setName("发卡人B");staffC.setName("发卡人C");staffA.start();staffB.start();staffC.start();}}class IssueClimbingCard extends (1) {private (2) int ClimbingCardNum = 1;@Overridepublic void (3) {while(true){synchronized(this.getClass()){if(ClimbingCardNum <= 100) {try {(4); // 此处睡眠10毫秒} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "：发放第"+ (5)+ "号登山卡；");ClimbingCardNum ++;} else {System.out.println(Thread.currentThread().getName() + "：100张卡已全部发放完毕！");break;}}}}}