There is an ASDM version available that uses OpenJRE and does not require Oracle Java. See "asdm-openjre-7131-101.bin" for example:
It's still Java but the open source variant. It does not require Java to be installed on the client PC.
While ASA hardware end-of-sale has been announced, the software (i.e. running on Firepower hardware or as ASAv image) will continue to be sold and supported for years to come.