Toxic Code Snippets on Stack Overflow

Online code clones are fragments that copied from software projects or online sources to Stack Overflow as examples. Due an absence of a checking mechanism after the has been Overflow, they can become toxic snippets, e.g., suffer being outdated violating original license. We present study on and their toxicity by incorporating two developer surveys large-scale clone detection. A survey 201 high-reputation answerers (33 percent response rate) showed 131 participants (65 percent) have ever notified 26 them (20 rarely never fix code. 138 (69 check for licensing conflicts between snippets Overflow's CC BY-SA 3.0. 87 visitors shows experienced several issues answers: mismatched solutions, incorrect buggy 85 not aware 3.0 license enforced 66 when reusing snippets. Our detection found pairs 72,365 Java 111 open source in curated Qualitas corpus. analysed 2,289 non-trivial candidates. investigation revealed strong evidence 153 project Overflow. 100 (66 be outdated, which 10 were harmful reuse. Furthermore, we 214 could potentially violate appear 7,112 times 2,427 GitHub projects.