Programming is just one aspect of being a software developer, You already are touching on design by your mention of OOP, the syntax, data structures, etc should

Programming is just one aspect of being a software developer, You already are touching on design by your mention of OOP, the syntax, data structures, etc should come fairly naturally after some experience but learning proper design patterns is also very important to progressing as a developer. Also, I'd recommend really delving into some projects on your own, if you are applying to programming jobs and haven't spend (at minimum) hundreds of hours programming on your own projects you can't expect to succeed in the interview. When I decided to pursue dev as a full-time career I spent about 3 months doing nothing but writing code all day, for my own projects, they were just stupid things I thought would be cool at the time but it taught me a lot and led to getting hired. Also, in my work experience, the ability to just get things done (or elegantly explain why something is not possible given current constraints) is what matters. Get the basics down, get some self-projects under your belt and then go into a job with the mindset that you are going to get things done, even if you have to go home and spend extra time at first, its worth it as you will keep learning and progressing. Overall, its not about knowing every possible aspect of a language or having everything memorized, its being able to take resources you have available (which includes search engines) and finding a solution to a problem. Even experienced developers (people I work with who have 10, 15 years exp) still spend plenty of time doing research on given topics, in software development its expected that you can do research productively to learn to solve a particular problem, if you haven't already encountered it, no one would, or at least should, expect you to have every possible solution memorized.