Analysis of Garbage Collection Algorithms and Memory Management in Java

Significant elements of the Java Virtual Machine (JVM), as a part of the Java Platform, Standard Edition (Java SE), crucial for automatic memory management are various Garbage Collection (GC) algorithms. Since implementation of the Java Development Kit (JDK) is continuously being improved, it is difficult to ignore several new Java Enhancement Proposals (JEPs) correlated to memory management in JVM. Several different garbage collectors are implemented in addition to the existing aged Serial, Parallel, and Concurrent Mark & Sweep (CMS) GC algorithms, as well as newer Garbage-First (G1) GC. The major progress since JDK 10 is making Parallel Full GC for G1, as a default multi-threaded GC when performing collections on an entire heap. Redundant overheads could appear when GC algorithms perform garbage collection too frequently, or a too large amount of memory could be allocated when garbage is not collected regularly. The goal of new algorithms' features is optimizing the overall process of releasing space so that pause times do not affect applications' performances negatively. This paper explores several garbage collectors available in JDK 11 by using selected benchmarking applications of the DaCapo suite for comparison of the number of algorithms' iterations and the duration of the collection time.