Which came first, Harry Potter or Java?

Java came first, by 2 years. Sun Microsystems announced Java publicly.

Side by side

Harry Potter

Bloomsbury published the first book in June 1997 with a print run of 500 copies, most of which went to libraries, after twelve other publishers had rejected the manuscript. The company's chairman gave the first chapter to his eight-year-old daughter, who demanded the rest. It came out the same year as Netflix was founded and a year before Google.

Java

Java was announced in May 1995, having started in 1991 as a project called Oak aimed at interactive television — a market that did not exist yet. Its promise was "write once, run anywhere", achieved by compiling to bytecode for a virtual machine rather than to a specific processor. JavaScript arrived seven months later and was named after it purely as a marketing decision; the two languages are unrelated.