The topics that I've already worked on:

• Internationalization Localization
• JDBC Blob Management : SQL queries to chunknize the blobs into sub-blobs making the treatment light for HeapMemory for Oracle DB
• Multi-Threading issues: Queuing, optimizing treatment duration, HeapMemory usage by using Java 8 lambdas expression and other new features
• Algorithmic and Mathematics (statistics) background: Optimizing the choice of right containers: for ex: ArrayList LinkedList
• JMH library for benchmarking: which gives an accurate vision of code running consumption (CPU)