Become a expert at java

Question

what is best thing to do after complete java course at this application to become a expert?
what should we learn?

Answer 1

https://www.sololearn.com/discuss/1858477/?ref=app
https://www.sololearn.com/discuss/551450/?ref=app
https://www.sololearn.com/discuss/2027323/?ref=app
https://www.sololearn.com/discuss/1775294/?ref=app
https://www.sololearn.com/discuss/1650884/?ref=app
https://www.sololearn.com/discuss/537271/?ref=app