Yes this problems coming due to poor service of ITD department...From 3CB-CD and other all forms updated by department last year only since then there are many updates on java platefrom.
These forms are working as usual on the old java version.
Myself also try to call callcentre but its waste of time only.
Dear Sir if you remove to Java 8 then it should be noted that you cannot able to run DSC which is mandatory in your case. So my sugesstion as I am doing ...Use 2 Computers - One to genrate .X M L and other for uploading.
Further you can take any programming expert help who can run both plateform same time.
If you got another solution then pls let me know two...as myself too suffering hard on this.
Please say to professional collegae raise voice to department. Otherwise ...