Here's my 5 cents
Presentation
Android, Angular.JS WebClient, OAUTHv2
API
REST, Jersey (JAX-RS), Jackson (JSON de-/serialisation), DTO-objects (different from business logic models)
Business Logic
Spring for DI and Event handling. DDD-ish approach of model objects. Longer running jobs are offloaded with SQS in worker-modules.
DAO
Repository model with Spring JDBC-templates to store Entities.
Redis (JEDIS) for Leaderboards, using Ordered Lists.
Memcache for Token Store.
Database
MySQL, Memcached, Redis
