Args guaranteed to be non-null?

Question

In the following program, if this is executed (e.g. via command line), is args JVM independently guaranteed to not be null?

public class test {
    public static void main(String[] args) {
    }
}

Answer 1

Short answer: yes, it may have length 0 but will not be null.

Answer 2

I can find no statement in the Loading, Linking, and Initializing section of the The Java Virtual Machine Specification that requires the arguments to be non null.

So it must be assumed that null is permitted, and, pedantically, your program should be prepared to handle null arguments. Even if in typical runtime environments, such as starting a Java program using the java program to start a JVM on Linux, it will never be the case that the arguments are null.

Answer 3

Double-clickable Application Bundles on MacOS still have a non-null array passed to main, even though there is no command line per-se.

The JVM specification does not specify if the array parameter to the main method can be null. See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-5.html#jvms-5.2

However, the convention is that it will be non-null and it is unlikely that a JVM vendor would break that convention at this point.