java heap memory usage monitoring

holds the cleaner fails), it is placed in the reference class pending list static variable.Then there is another Referencehandler thread, followed by the pending list, and if you see the object type is cleaner, it will execute its clean (); If other types are placed in the Referencequeue,Such applied code can drag out these theoretically dead objects from the queue, which is a much lighter and better mechanism than finalizer.Reference:is Java directb

display of DataView is inaccurate.Workaround (Pending validation):1. Use the built-in Zabbix variable proc.cpu.util[2. Modify the commands in the script, using the following method instead:First, get the PID of the process name, and then combine top to run the following command:Top-b-n 1-p $pid 2>1 | Awk-v pid= $pid ' {if (= = pid) print $9} '3. Modify the commands in the script, using the following method instead:The PID of the process name is obtained first, and then the relevant data is read

, and other data. this frame is similar to the activity record concept in the compilation principle.From the perspective of Java's allocation mechanism, the stack can be understood as follows: a stack is a process or thread created by the operating system (a thread in an operating system that supports multithreading) the storage area created for this thread has the advanced and later features.Each Java application corresponds to only one JVM instance,

Reprinted from HTTPS://GITHUB.COM/PZXWHC/MINEKNOWCONTAINER/ISSUES/25Including:1. Stack Overflow (stackoverflowerror)2. Heap overflow (Outofmemoryerror:java heap space)3. Permanent generation overflow (outofmemoryerror:permgen space)4. Outofmemoryerror:unable to create native threadThe Java Virtual Machine specification specifies that the JVM's

By default, Tomcat can use 128 MB of memory. In large application projects, this memory is not enough. If it is mild, the system performance will drop sharply When it is heavy, the system cannot run, which affects the system stability. When the memory is insufficient, the common problem is to report the Tomcat memory b

The JVM can use 2 different kinds of memory: heap memory and out -of-heap memory.Heap memory is fully allocated and freed by the JVM, and if the program does not have a defective code that causes memory leaks, you will not encount

Heap Memory Setting principleJVM heap memory is divided into 2 blocks: Permanent space and heap space. Permanent is the persistent generation (Permanent Generation), which mainly holds Java class definition information, w

a type, such as:char ch; float x; int a,b,c;CH is a character type and is allocated to 2 bytes of memory. Different types of variables have different bytes allocated in memory, and they are stored in different ways.Therefore, it is necessary to determine the type of the variable before assigning a value, and determine the type of the variable, that is, determine the size of the

character array are two completely different objects. System. out. println ("Hello". length ());Char [] cc = {'h', 'I '};System. out. println (cc. length ); 3. Create a String object:Because a String object is widely used (it is an object, in general, the object is always allocated memory in heap), Java aims to save memory