Suggestion for switching to Java developer from support oracle technology

Hi all,

I have 4 years of experience in support project technology is oracle based erp.. i don't thing that technology has more opportunities outside.. I am planning to switch to switch to java. I aleeady went through java training when i joined my first mnc for 4 months. Now i am thinking to grill up sometopics by watching durgasoft YouTube channel... please tell me what are the things i can refer for cracking interview... like spring boot, framework, micrservices..