When you do an SA attach. You will see the following warning messages:

     Warning! JS Engine can't start, some commands will not be available.

If before the attach you first do a "verbose true" command, you will see the reason for the failure:

 java.lang.RuntimeException: javax.script.ScriptException: TypeError: so["has(java.lang.String)"] is not a function in sa.js at line number 133

This has been broken since 9 since because the Nashorn engine allows Java access only for public classes in exported packages of modules. SA does not export any API packages.

This also shows up when running SOQL and JSDB tools:

    java --add-modules jdk.hotspot.agent sun.jvm.hotspot.tools.soql.SOQL <pid>
    Warning: Nashorn engine is planned to be removed from a future JDK release
    javax.script.ScriptException: TypeError: sapkg.runtime.VM.getVM is not a function in sa.js at line number 54
    javax.script.ScriptException: TypeError: sapkg.runtime.VM.getVM is not a function in sa.js at line number 54
    java.lang.RuntimeException: javax.script.ScriptException: TypeError: so.getIds is not a function in sa.js at line number 147