[fsckboy]

jar files are zip files, so they don't contain "self extract" code, instead they are associated with already installed extraction code.

however, once extracted, jar files do contain executable code, and that is a security issue. the java model pays attention to security, but if code can do something, it can do something bad. if it can't do something, it's not very useful, is it.

[notepad0x90]

the windows kernel executes a self extracting 7z archive, java.exe extracts and executes .jar files. If the 7z self extractor was .net CLR bytecode it would operate very much the same as .JAR files. to your point though, the primary purpose of JAR files is not to compress and transport other files, they're supposed to be executables only. From a user's perspective, abuse potential is the main difference.