Too Long; Didn't Read
You may need a lot of coding to become a proficient Java developer. Practice is the key to learning code. Malcolm Gladwell’s 10,000-hour rule: practicing a particular skill (including coding and programming) for about 20 hours per week and ten years in total is key to success in any field. Start small. Start slow and scope your skill so as not to get overwhelmed at the beginning and, consequently, make the whole process easier for yourself. Read about Java regularly to explore more, stay motivated, and get up-to-date, but remember to code more than you read.