Force.com Ant Migration Tool version 51.0 is requires Java Version 11 and later.
Spring 21 Release Note Link: https://help.salesforce.com/articleView?id=release-notes.rn_deployment_ant_migration_java_11.htm&type=5&release=230
ANT Migration Tool Guide: https://developer.salesforce.com/docs/atlas.en-us.daas.meta/daas/meta_development.htm
Earlier Ant Migration Tool versions (< 51.0 version) continue to support Java version 7 or later