NPEFix: Automatic Runtime Repair of Null Pointer Exceptions in Java
This addresses a common issue for Java developers by providing an automatic runtime repair tool, though it is incremental as it builds on existing exception handling methods.
The paper tackled the problem of null pointer exceptions in Java by proposing nine alternative execution semantics to repair them at runtime, achieving repair rates of 10 out of 11 field bugs and 318 out of 519 seeded failures.
Null pointer exceptions, also known as null dereferences are the number one exceptions in the field. In this paper, we propose 9 alternative execution semantics when a null pointer exception is about to happen. We implement those alternative execution strategies using code transformation in a tool called NPEfix. We evaluate our prototype implementation on 11 field null dereference bugs and 519 seeded failures and show that NPEfix is able to repair at runtime 10/11 and 318/519 failures.