Null dereference is a common type of runtime failure in Java programs, and it is necessary to verify whether a dereference in the program is safe. However, previous works often have redundant path exploration and high false positive rate. In this paper, we propose a merged null dereference verification (MNDV) approach. MNDV employs a backward, path-sensitive inter-procedural analysis technique to verify a given dereference as safe or potentially unsafe. It uses a branch merging strategy to remove redundant paths, and a method call's relevance to the null references is checked to determine whether it is necessary to explore the internal codes of the method. We have evaluated the approach in some standard benchmark programs. Compared with some existing approaches, our approach reduces false alarm rate and effectively reduce time and memory consumption.

中文翻译：

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通过合并分支优化需求驱动的空解引用验证

空解引用是Java程序中常见的一种运行时失败，需要验证程序中的解引用是否安全。然而，之前的工作往往存在冗余路径探索和高误报率。在本文中，我们提出了一种合并的空解引用验证 (MNDV) 方法。MNDV 采用向后的、路径敏感的过程间分析技术来验证给定的取消引用是安全的还是潜在的不安全的。它使用分支合并策略去除冗余路径，并检查方法调用与空引用的相关性以确定是否有必要探索方法的内部代码。我们已经在一些标准基准程序中评估了该方法。与现有的一些方法相比，