Libraries can be useful despite imperfections, and poor design decisions can occur in overall good libraries. So we can't judge too harshly. Having said that:

Libraries can be useful despite imperfections, and poor design decisions can occur in overall good libraries. So we can't judge too harshly. Having said that: 1) iText PDF library used to have some fairly poor & duplicated code. Column layout was a highlight. Also strange ideas overemphasizing subclasses, eg. for paragraph styles. (Correct approach: use values rather than types.) 2) Tomcat webserver back around 2007 used to have some amazing 'clustering' code to deploy your webapp across multiple servers. But it lacked proper knowledge & hence control of what it was doing. IIRC there was no clear master, and a server couldn't tell what had been started on it versus what had been replicated since a peer was seen to be running it. Effect: replication would be additive only, contexts would just replicate everywhere uncontrolled, and there was no good way to stop/ undeploy an app across the cluster.