J2EE - (EJB, JMS, JCA, JAX-RS, JAX-WS/SAAJ/WS-Security, JSP/JSF)

Spring - (DI/SpEL, JdbcTemplate/Repository, MVC, WebFlow, RESTful, Security)

SparkJava, Play/Akka, GWT/GXT.

Elasticsearch, Kafka, Storm, Spark, RabbitMQ, Hadoop (HDFS, Hive, Pig)

MySQL, PostgreSQL, Oracle, Vertica.

MongoDB, Cassandra, Redis, Couchdb.

Flyway, Liquibase.

AWS - (Cognito/IAM/Lambda/Dynamodb/Redshift/EC2/ECS/API Gateway/SES/CLI/S3/SNS/Cloudfront/CloudTrail/Transcoding)

Google Cloud - (BigQuery, AppEngine, PubSub, IAM, StackDriver, Cloud SQL)

Android

AngularJS, ReactJS.

Docker.

Python, Scala, Kotlin.