This. I learnt Java in 2004-5, when 1.4 was dominant and O'Reilly books were a much better training resource than whatever you found on the Internet. Concatena

This. I learnt Java in 2004-5, when 1.4 was dominant and O'Reilly books were a much better training resource than whatever you found on the Internet. Concatenating of thousands of individual Strings was already considered a well-known performance killer back then. Interesting to see this in the wild in 2026.