garbage collection analysis

an obscure storage problem. When programming in Java, the garbage collection mechanism can greatly shorten the time. Second, it protects program integrity. Garbage collection is an important part of Java's security policy. One potential drawback of garbage

? Before the garbage collector reclaims the Java heap , it first determines which of the object instances are "alive" and which are "dead" (that is, no references exist). In many textbooks, the reference counting algorithm is used to determine whether an object can be recycled: Add a reference counter to the object, each quoted once, and the counter plus 1;When the reference fails, the counter is reduced by 1; When the counter remains at 0 o'clo

Garbage collector and Memory allocation policy (ii)--garbage collection algorithm JAVAJVM garbage collectorSimple understanding of the idea of algorithms1. Mark-Sweep algorithmMark-sweep algorithm is divided into two stages: Mark and clear the objects that need to be recycled (see the accessibility

　　Based on the "in-depth understanding of Java Virtual Machines", this book summarizes　　I. About several concepts: (tag garbage algorithm, garbage collection algorithm, garbage collector)There are two ways to find JVM garbage: The reference counting method/accessibility algo

The current commercial virtual machine garbage collection uses the "generational collection" algorithm, that is, according to the different life cycle of the object, divided into several pieces of memory, generally for the Cenozoic and the old era, different generations according to its characteristics of the use of the most appropriate

efficient. In the absence of a garbage collection mechanism, it may take a lot of time to solve a hard-to-understand memory problem. When programming in the Java language, the garbage collection mechanism can greatly shorten the time. Second, it protects the integrity of the program, and

-GC of waste recycling mechanism JavaScript has an automatic garbage collection mechanism (Gc:garbage collecation), in other words, the execution environment is responsible for managing the memory used during code execution. Principle: The garbage collector periodically (periodically) identifies those variables that are not being used, and then releases their m

difficult to solve the problem of mutual circular referencing between objects. As a result, mainstream Java virtual machines do not manage memory in this way.2. Accessibility analysisThe mainstream realization is the accessibility analysis. The basic idea is to search through a series of objects called "GC Roots" as the starting point, searching through the path called the reference chain (Reference Chain), and proving that the object is not availabl

of programming. This gives Java virtual machines some advantages. First, it can make programming more efficient. In the absence of a garbage collection mechanism, it may take a lot of time to solve a difficult memory problem. When programming in the Java language, the garbage collection mechanism can greatly shorten t

Overview Program counters, local method stacks, virtual machine stacks are born with threads, and are extinguished with threads. Java heap and method area are different, this part of memory allocation and recycling are dynamic, the garbage collector is concerned about this part of memory. algorithm for determining whether an object is garbage The JVM does not use a reference-counting algorithm to manage me

OverviewThe program counter, the local method stack, and the virtual machine stack are threaded and extinguished with the thread. Java heap and method area are different, this part of memory allocation and recycling is dynamic, the garbage collector is concerned about this part of memory.An algorithm for judging whether an object is garbageThe JVM does not use the reference counting algorithm to manage memory, and the main thing is that reference coun

: When to trigger GC Where to dispatch persons: select different garbage collectors based on different generations Why is there a relatively long and frequent time for sanitation in some places: the parameter settings of the young generation, the old generation, and the long-lasting generation often produce full GC? Health Task failed: OOM (outofmemoryerror) and Java Memory leakage monitoring (find out the cause of Memory leakage) sometimes

ParNew collector for JAVA garbage collector, parnew for garbage collection 1, Features The ParNew collector is a type of Garbage Collector in Java virtual machines. It is a multi-threaded version of the Serial collector. In addition to using multiple threads for garbage

collection mechanism is disabled, if the root buffer is full, the root may not be recorded. The root of unrecorded records will not be analyzed and processed by this algorithm. If they are part of a cycle reference period, they will never be cleared, resulting in memory leakage. Even if the garbage collection mechanism is unavailable, the root may be recorded be

JVM-Garbage Collector, jvm-garbage collection This article mainly introduces several JVM garbage collectors. As shown below, the three above are the new generation collectors, The following three are the collectors of the old generation. The G1 collector can be used for the collect