From the documentation about naming packages in Java:
In some cases, the internet domain name may not be a valid package
name. This can occur if the domain name contains a hyphen or other
special character, if the package name begins with a digit or other
character that is illegal to use as the beginning of a Java name
This means you can't use a digit as the first character of a package (or a class, interface or variable name, for that matter).
To clarify, you can name your app 1abcxyz, it's only the package name that cannot start with a digit (you could use oneabcxyz
instead of 1abcxyz
for example). Having a package name different from your company's website should not influence communications between your app and your company's servers.