我试图用VS代码运行Java应用程序，但是出现以下错误：
javac : The term 'javac' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
我该如何解决？
**几个月前，我能够在VS Code中运行Java应用程序，现在它向我显示此错误。