如何解决找不到或加载主类错误？

Question

I am getting this error if I add new component to my frame if I remove it then it works.

I done this troubleshooting

(1)deleting index folder and restart computer and netbeans

(2)increased heap size in conf file

(3)set environment variable in windows system as

  :-User variable name = CLASSPATH
  :-variable value = C:\Program Files (x86)\Java\jdk1.8.0_40\bin;C:\Program Files (x86)\Java\jre1.8.0_40\bin;.

  :-System variable name :-Path

  :-System Variable value:-C:\ProgramData\Oracle\Java\javapath;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files\Microsoft\Web Platform Installer\;C:\Program Files (x86)\Java\jdk1.8.0_40\bin;C:\Program Files (x86)\Java\jre1.8.0_40\bin 

but the problem persists

if i add new component(radiobutton,label,scrollpane) it gives me this error:

Answer 1

you can try Clean and build your project, if it doesn't work, you can check the posts from
Netbeans - Error: Could not find or load main class ,
Error: Could not find or load main class (netbeans and java) or
What does "Could not find or load main class" mean?

Answer 2

With Java 11 you can start a class from the terminal with

java classname.java