how to monitor java memory usage

and fat some. Now the impression is still more profound. It seems like.. I'm off the topic ~ ~)Just speaking of full GC, the new generation of memory usage from 288K to 0 K, then this 288K exactly where? Are they all garbage collected by GC? No, of course not. I also deliberately new in the main method, an instance of the test class, where the instance of the test class is a small object, it should be allo

only be used to determine the content of the string on the stack, "=" indicates false, because every string is stored as a String object in the heap. 4. How to control the memory. Here we will show you how to use the jvm memory. Maximum memory of the current Virtual Machine: Runtime.GetRuntime(). MaxMemory (); Memory

Java.lang.Class instance, loading this type of ClassLoader instance, any one or more of the three is reachable state, Then this type cannot be uninstalled.The 8 JMX protocol provides a corresponding API interface for querying the memory usage and type loading information of the current virtual machine instance at run time. This is also the basis for many Java pe

IntroductionApp optimized memory optimization (order) as a small part of memory optimization in the app optimization series.Due to the relatively jerky memory-related knowledge, memory optimization used in the relevant tools, there are many proper nouns. There is a theoretical understanding of

Java memory allocation and management is one of the core technologies of Java, before we introduced the Java memory management and memory leaks and Java garbage collection knowledge, to

Originally from: Http://blog.csdn.net/rj042/article/details/6871030#commentsJava memory allocation and management is one of the core technologies of Java, before we introduced the Java memory management and memory leaks and Java g

In the previous few, we talked about the usage and the underlying implementation of synchronized, final, and voilate, all without a topic-java memory models (Java memory model, abbreviated JMM). The Java

Memory management and garbage collection are critical points for the JVM, and it is important to understand the basic strategies of memory management and garbage collection for the analysis of Java performance. This article describes the memory management and garbage collection of Sun JVM 6.0.1.

This article transferred from: http://www.infoq.com/cn/articles/java-memory-model-4Characteristics of volatileWhen we declare that the shared variable is volatile, the read/write to this variable will be very special. A good way to understand the volatile characteristics is to treat a single read/write of the volatile variable as a synchronization of these individual read/write operations using the same loc

IntroductionJava has been learning for some time, always feel that some things learned is not very proficient. Like what exactly is the Java memory area? How did the program run? How is the object stored? All of this has affected my familiarity with my own code.A run-time data regionIn the course of executing a Java program, the

the opts of the Java process at runtime.JPS: Similar to PS on UNIX, used to show the local Java process, you can view the local running a few Java programs, and display their process number.Jstat: A very strong monitoring VM memory tool. can be used to monitor the size of various heap and non-heap sizes and their

Jinfo: You can output and modify the opts of the Java process at runtime.JPS: Similar to PS on UNIX, used to show the local Java process, you can view the local running a few Java programs, and display their process number.Jstat: A very strong monitoring VM memory tool. can be used to monitor the size of various heap a

the Storestore barrier will ensure that all of the above normal writes are flushed to the main memory before volatile writes.What's interesting here is the storeload barrier behind the volatile writing. The purpose of this barrier is to avoid volatile writes and re-ordering of possible volatile read/write operations. Because the compiler often cannot determine exactly after a volatile write, whether to insert a storeload barrier (for example, a volat

This article belongs to author original, the original text is published in Infoq:http://www.infoq.com/cn/articles/java-memory-model-4Characteristics of volatileWhen we declare that the shared variable is volatile, the read/write to this variable will be very special. A good way to understand the volatile characteristics is to treat a single read/write of the volatile variable as a synchronization of these i

stack is very similar, but the difference is that the virtual machine stack executes Java methods (that is, bytecode) services for the virtual machine, while the local method stack serves the native method used by the virtual machine. The language, usage, and data structure of the methods used in the local method stack in the virtual machine specification are not mandatory, so the virtual machine can imple

the Storestore barrier will ensure that all of the above normal writes are flushed to the main memory before volatile writes.What's interesting here is the storeload barrier behind the volatile writing. The purpose of this barrier is to avoid volatile writes and re-ordering of possible volatile read/write operations. Because the compiler often cannot determine exactly after a volatile write, whether to insert a storeload barrier (for example, a volat

to avoid volatile writes and re-ordering of possible volatile read/write operations. Because the compiler often cannot determine exactly after a volatile write, whether to insert a storeload barrier (for example, a volatile write method immediately return). To ensure the correct implementation of volatile memory semantics, JMM has adopted a conservative strategy here: Insert a storeload barrier behind each volatile write or before each volatile read.

all of the above normal writes are flushed to the main memory before volatile writes.What's interesting here is the storeload barrier behind the volatile writing. The purpose of this barrier is to avoid volatile writes and re-ordering of possible volatile read/write operations. Because the compiler often cannot determine exactly after a volatile write, whether to insert a storeload barrier (for example, a volatile write method immediately return). To

　　Java Memory allocation and management is one of the core technologies of java, before we introduced the Java memory management and memory leaks and Java garbage collection knowledge,

simple arrays For example, each row of a two-dimensional array is a separate array objectmemory usage of a single arrayA one-dimensional array is an object, and an array has an object header, but this object takes up 12 bytes and an additional 4 bytes to store the length of the array. How many bytes are required for each element, depending on the type of element. Each element requires 4 bytes to store its reference. And if the total number of by