I thought his comment was more along the lines of "I cannot imagine writing industrial-strength versions of all of these things Lucene gives me." Yes, you can

I thought his comment was more along the lines of "I cannot imagine writing industrial-strength versions of all of these things Lucene gives me." Yes, you can write a spellchecker in 21 lines of code, that doesn't necessarily mean it will be fast enough to be a component in website search or that it will be any kind of a pleasure to query or maintain the word corpus. I can put together toy versions of many things Lucene provides pretty easily in my own time. Building useful, dependable versions of most anything takes a nontrivial amount of time and effort, so it's smart to restrict my usage of toys to understanding the concepts.