Java visualizer integer code#
Java visualizer integer series#

This is where the Just In Time(JIT) compiler stores compiled code blocks that are often accessed. To avoid that it’s possible to set a limit on meta-space used with the XX:MetaspaceSize and -XX:MaxMetaspaceSize flag in which case the application might just throw out of memory errors. If this space keeps growing, the OS might move data stored here from RAM to virtual memory which might slow down the application. This space is used by the class loaders to store class definitions. This is what used to be Permanent Generation(PermGen) Space in earlier versions of JVM. This is part of the native memory and doesn’t have an upper limit by default.

The stack memory limit can be set using the Xss flag. This is where thread-specific static data including method/function frames and pointers to objects are stored. This is the stack memory area and there is one stack memory per thread in the process.

Old generation: Old generation or “Tenured Space” is where objects that reached the maximum tenure threshold during minor GC live.

This is divided into two halves, S0 and S1.

Survivor Space: This is where objects that survived the minor GC are stored.

When we create a new object, memory is allocated here.

Eden Space: This is where new objects are created.

This space is managed by “Minor GC” also sometimes called “Young GC”

Young generation: Young generation or “New Space” is where new objects live and is further divided into “Eden Space” and “Survivor Space”.

Heap is further divided into “Young” and “Old” generation space. The entire heap memory is not committed to the Virtual Machine(VM) as some of it is reserved as virtual space and the heap can grow to use this. The size of heap memory can be controlled using the Xms(Initial) and Xmx(Max) flags.

This is the biggest block of memory area and this is where Garbage Collection(GC) takes place. This is where JVM stores object or dynamic data. Let us see what the different areas are for: Heap Memory This is the native memory allocated by the OS and the amount depends on OS, processor, and JRE. Below is the memory available to a JVM process and is allocated by the Operating System(OS). JVM memory structureįirst, let us see what the memory structure of JVM is. If you haven’t read the first part of this series, please read it first as I explained the difference between the Stack and Heap memory there which would be useful to understand this chapter. In this chapter, we will look at the memory management of the Java Virtual Machine(JVM) used by languages like Java, Kotlin, Scala, Clojure, Groovy, and so on.

Java visualizer integer series#

I hope the series would give you some insights into what is happening under the hood of these languages in terms of memory management. In this multi-part series, I aim to demystify the concepts behind memory management and take a deeper look at memory management in some of the modern programming languages.