Yes, the main method is compulsory in Java for a standalone Java program to run.

In Java, the main method is the entry point for a program, which means that the Java Virtual Machine (JVM) looks for the main method in the specified class and executes it when the program is run. Without the main method, the JVM won't know where to start the program execution.

The main method has the following signature: 

public static void main(String[] args)

It takes an array of strings as input, which represents the command-line arguments passed to the program. The main method must be declared as public, static, and void so that the JVM can access it without creating an instance of the class.

Note that the main method is not compulsory in all types of Java programs. For example, in a web application or a Java applet, the entry point is typically defined by the container or the web browser, and the main method may not be needed.