Can a Java Program Have Multiple Main Methods?

Is it possible to have more than one main method in a Java application?

// Example of multiple main methods
public class Example {
    public static void main(String[] args) {
        System.out.println("Main method 1");
    }

    public static void main(String[] args, int num) {
        System.out.println("Main method 2");
    }
}

In Java, the 'main' method serves as the entry point for any standalone Java application. However, the structure and signature of the 'main' method must adhere to specific rules. This answer clarifies whether having multiple 'main' methods in a single Java class is feasible and what that entails.

public class MainExample {
    public static void main(String[] args) {
        System.out.println("Standard main method");
    }

    public static void main(String[] args, int number) {
        System.out.println("Overloaded main method with int parameter");
    }
} // Only the first main method will be executed by the JVM.

Causes

• Java permits method overloading, meaning you can define multiple methods with the same name but different parameter types or number of parameters.
• Each overloaded 'main' method must have unique signatures.

Solutions

• While you can define multiple methods named 'main', only one of them will act as the entry point of the program when executed from the command line or an IDE.
• For the JVM to identify the entry point correctly, the 'main' method must follow the Java Signature: public static void main(String[] args).

Mistake: Assuming multiple main methods can execute simultaneously.

Solution: Only the properly defined main method will be executed. Others can be used for method overloading but will not serve as entry points.

Mistake: Forgetting to use the correct parameter signature for the main method.

Solution: Remember that the signature must be public static void main(String[] args). Any deviation will prevent proper execution.