Memory and resource leak defects and their repairs in Java projects

Abstract

Despite huge software engineering efforts and programming language support, resource and memory leaks are still a troublesome issue, even in memory-managed languages such as Java. Understanding the properties of leak-inducing defects, how the leaks manifest, and how they are repaired is an essential prerequisite for designing better approaches for avoidance, diagnosis, and repair of leak-related bugs.We conduct a detailed empirical study on 491 issues from 15 large opensource Java projects. The study proposes taxonomies for the leak types, for the defects causing them, and for the repair actions. We investigate, under several aspects, the distributions within each taxonomy and the relationships between them. We find that manual code inspection and manual runtime detection are still the main methods for leak detection. We find that most of the errors manifest on error-free execution paths, and developers repair the leak defects in a shorter time than non-leak defects. We also identify 13 recurring code transformations in the repair patches. Based on our findings, we draw a variety of implications on how developers can avoid, detect, isolate and repair leakrelated bugs.

Software Micro-Rejuvenation for Android Mobile Systems

“…A container is an object that contains references to other objects, and these may be related to Java data structures like lists and sets. The aging problem occurs when the objects' references inside these containers are inserted but never removed [29,30,31]. The accumulation of unused objects causes the increase of the GC overhead (which consumes CPU to inspect the heap, and slows down the entire process), and eventually the exhaustion of heap memory up to software hang or crash.…”

Evaluating an Interactive Memory Analysis Tool: Findings from a Cognitive Walkthrough and a User Study

“…Memory leaks [35] in managed languages occur if objects no longer needed remain reachable from garbage collection roots (e.g., static fields or local variables) due to programming errors. For example, objects may accumulate over time when a developer forgets to remove them from long-living data structures [115].…”

“…received the labels 'Detects Growth In Chart' as well as 'Recognizes Growth as Problem'. We adopted and adjusted an iterative labelling process [35] that is similar to Open Coding [100]. First, a set of possible observation labels and statement labels had to be formed.…”

A Comprehensive Study on Software Aging across Android Versions and Vendors

“…Popular tools for findings memory leaks (i.e., objects that have not been deallocated) in C and C++ software include Valgrind (Nethercote and Seward, 2007) and AddressSanitizer (Serebryany et al, 2012), which traverse at run-time the heap memory, starting from the program's root set of references (e.g., pointers on the stack) and following the pointers inside the objects to find the unreachable (i.e., leaked) ones. For the Java programming language, which avoids memory leaks with automated garbage collection, research has been focused on memory bloat, i.e., unnecessary objects that are still referenced by the program but will not be used, thus increasing the load for memory management and impacting on the performance of the program (Ghanavati et al, 2019). Xu and Rountev (2013) and Jump and McKinley (2007) analyzed in detail memory bloat issues caused by the accumulation of unused objects in Java containers (e.g., the HashMap and ArrayList data structures), and proposed techniques for analyzing the heap growth over time to identify objects suspected of bloating memory, based on the age, the time-to-last-access, and the contribution to memory consumption.…”