In Java, Up to Java 6 it was possible to do this using the Static Initialization Block. For solve the problem to a execute java program without having main method.

For example we have writing the following code using static block:

 
public class
CheckWithoutMain{  
  static{ 
  System.out.println("static block is
Executed");  
  System.exit(0);  
  }  
}  

Output: (In JDK 6)

The System.exit (0); is used to the program exit before the JVM is looking for the

main method, otherwise error will be thrown:

Exception in thread “main” java.lang.NoSuchMethodError:main

In Java 7 & above, however, this does not work anymore, even though it compiles,

the following error will appear when you try to execute it:

The program compiled successfully, but main class was not found. Main class

would contains method: public static void main (String [] args).

Output: (In JDK 8)

So, we have only execute a java program without having main method up to valid Java versions 6.