Packaging the legacy application and its specific JRE in a container limits exposure to the host operating system.
Because public updates ceased over a decade ago, Java 1.4.0 does not contain modern security patches. It is completely exposed to vulnerabilities discovered after 2008, meaning it should never be deployed on public-facing internet servers. How to Safely Download Java 1.4.0 java 1.4 0 download
If you cannot use the Oracle Archive, some community-maintained open-source repositories preserve old binaries. Packaging the legacy application and its specific JRE
If you cannot use the official archive, some community-maintained sites host the installers: Internet Archive java 1.4 0 download