In some programming languages/platforms (e.g. Java), the product that you distribute can indeed be reverse engineered in a way that most original names are kept

In some programming languages/platforms (e.g. Java), the product that you distribute can indeed be reverse engineered in a way that most original names are kept. But there are tools to obfuscate the code before turning it into something executable. In some others (e.g. C), the executable that's distributed pretty much talks the language of the underlying machine, so the original code structure and naming are not preserved.