Java codebases experience

Looking to explore the backend systems and language

Seems Java is used heavily across many organisations and a lot of job postings involve Java compared to Golang, Python, Ruby, Node etc

Wanted to know your experience with java codebases, how's the code quality, what issue do you'll face or in general your experience

Considering several companies might be running java due to legacy code or upgrades issues. Are you'll planning to migrate these services to another language?