The server requires that Java be installed on the system and made available to the server, and it must be installed before running setup. If the setup tool does not detect that a suitable Java environment is available, it will refuse to run.

To ensure that this does not happen, the setup tool should be invoked with an explicitly-defined value for the JAVA_HOME environment variable that specifies the path to the Java installation that should be used. For example:
env JAVA_HOME=/ds/java ./setup
If this still does not work for some reason, then it can be that the value specified in the provided JAVA_HOME environment variable can be overridden by another environment variable. If that occurs, try the following command, which should override any other environment variables that can be set: