As other users said, It depends on what would be the purpose of learning it. I'm currently consuming data from different API's and currently using Python. So th

As other users said, It depends on what would be the purpose of learning it. I'm currently consuming data from different API's and currently using Python. So the next step is learning Java and some Apache technologies: Kafka, Hadoop, Storm which are built in it. I also will need to code a native mobile app and Java is the language of choice for Android.