What happens if main method is declared private

What happens if main method is declared private

Answer: 

Anything other than public program will not run.

Declaring method as private method will not be visible out side of the class and you will not be able to execute the class as a standalone java program. Any java class that needs to be executed as a standalone file needs to have a main method that is public, static and returns a void. Otherwise the Java compiler would not recognize the file as an executable standalone java file and would not allow you to run it. If you run class you will get below exception:

Exception in thread "main" java.lang.NoClassDefFoundError: MainMethodTest (wrong name: com/javahonk/
MainMethodTest)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:791)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:472)

 

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