These are community-driven collections often found via GitHub search. They usually contain links to PDFs or Markdown files listing 100+ common interview questions.
pandoc full-book.md -o java-coding-problems.pdf --pdf-engine=xelatex java-coding problems pdf github
This yields a professional, table-of-contents-enabled PDF. This yields a professional, table-of-contents-enabled PDF
Here is a sample of the type of problems you will find in these repositories. Try to solve them before checking the solution links. Difficulty: Easy Description: Given an array of integers
If you want to find specific downloadable PDFs via Google, use these search operators:
Difficulty: Easy
Description: Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
Java Concept: Use a HashMap to reduce time complexity from $O(n^2)$ to $O(n)$.
Strictly speaking, this is not "problems" but "solutions" to classic problems. However, it is the most starred Java repo on GitHub.