What is PermGen space in Java?
A java. lang. OutOfMemoryError: PermGen Space is a runtime error in Java which occurs when the permanent generation (PermGen) area in memory is exhausted. The PermGen area of the Java heap is used to store metadata such as class declarations, methods and object arrays.
Is PermGen garbage collected?
The PermGen is garbage collected like the other parts of the heap. The thing to note here is that the PermGen contains meta-data of the classes and the objects i.e. pointers into the rest of the heap where the objects are allocated.
Why does Java 8 remove PermGen space?
The main reason for removing PermGen in Java 8 is: It is very hard to predict the required size of PermGen. It is fixed size at startup, so difficult to tune. Future improvements were limited by PermGen space.
What is PermGen error?
If you get the error message: java. lang. OutOfMemoryError: PermGen space this means that you have exceeded Java’s fixed block for loading class files. Permanent Generation Memory, unlike Java heap space, is the memory allocation for the classes themselves as opposed to the objects created.
What is the difference between PermGen space and Metaspace?
The default size of PermGen memory is 64 MB on 32-bit JVM and 82 MB on the 64-bit version….MetaSpace in Java 8 with Examples.
| PermGen | MetaSpace |
|---|---|
| PermGen always has a fixed maximum size. | Metaspace by default auto increases its size depending on the underlying OS. |
What is PermGen space and Metaspace?
In Java 8, PermGen method area replaced with MetaSpace. They have moved permGem to the separate memory in the native OS and that is called MetaSpace. It can by default auto increases its size. In MetaSpace, classes can load and unload during the lifespan of the JVM.
Is PermGen part of heap memory?
PermGen (Permanent Generation) is a special heap space separated from the main memory heap. The JVM keeps track of loaded class metadata in the PermGen. Additionally, the JVM stores all the static content in this memory section.
What replaced PermGen space in Java 8?
Metaspace
Simply put, Metaspace is a new memory space – starting from the Java 8 version; it has replaced the older PermGen memory space.
What is PermGen size?
PermGen is the memory area for storing class data like static variable,byte code and etc. By default 64 Mb is allocated for PermGen.