slim Although this thread is quite old, would Like to suggest checking out Interviewbit for folks who stumble upon this thread like I did: https://www.interviewbit.com/practice/

A Good hold on Data Structures and Algorithms. some imp java topics: oops concept, overloading and overiding, JDK, JRE, JVM All of the questions are mostly covered here: Core java interview Questions & Answers Last but not the least, go through the job description well, nothing would be asked outside it, atleast to crack interview that is sufficient.

Incase, your still looking out for more resources. Here's, one of my top pick for react interview questions: https://www.interviewbit.com/react-interview-questions/

No matter what competitive programming language you choose make sure to learn all the basics and in-built functions. Study the fundamentals of Data Structures and Algorithms and understand their application. Start participating in virtual contests like the one held in codeforces where you can better your coding skills later when your confident enough you can participate in real time contests hosted on various online platforms. Leaving you a link, you might find useful: https://qr.ae/pNKRCR ......