His “Decoding AP Computer Science A: For a High Schooler, By a High Schooler” has sold more than 200 copies since going on sale in February. At $10.99, Jawa makes 15 cents on each copy.

Get 10+ important coding and decoding multiple choice questions with detailed answers and explanations. Ideal for SSC, UPSC, Bank, Railways, and other competitive exams.

Jawa’s course, Decoding AP Computer Science A, has earned an average of 4.4 out of 5 stars from more than 100 reviewers on the Udemy site. Udemy offers 40,000 courses; 90 percent charge a fee ...