import java.util.Date;
public class hello

{
      
       public static void main(String[] args)

       {
          Date date=new Date();
          String hour=String.format("%tH",date);
          String minute=String.format("%tM", date);
          String second=String.format("%tS",date);
          System.out.println("现在是："+hour+"时"+minute+"分"+second+"秒");

       }

}
Exception in thread "main" java.lang.Error: Unresolved compilation problems:
    The type java.lang.CharSequence cannot be resolved. It is indirectly referenced from required .class files
    The method format(String, Object[]) in the type String is not applicable for the arguments (String, Date)
    The method format(String, Object[]) in the type String is not applicable for the arguments (String, Date)
    The method format(String, Object[]) in the type String is not applicable for the arguments (String, Date)

    at hello.main(hello.java:10)

好像不是这个问题。

import java.util.Date;
这一句有个叉叉。

在cmd下输入javac和java是有输出的，表明有jdk环境。

已解决就是那个叉叉的问题，点下那个叉叉选第二项就好了。
谢谢楼上各位。