Is PermGen space part of the heap?

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 is stored in PermGen space in Java heap?

The PermGen area of the Java heap is used to store metadata such as class declarations, methods and object arrays.

What is MetaSpace in Java 8 How does it differ from PermGen space?

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.

What is PermGen space in JVM?

The PermGen space contains the internal representation of the Java classes that JVM holds. The Permanent Generation is the garbage data that is collected in the same way as heap’s other parts collected. It is a special area of memory that contains meta-data of the program’s classes and the program’s objects.

What is Java heap size?

When the JVM is started, heap memory is created and any objects in the heap can be shared between threads as long as the application is running. The size of the heap can vary, so many users restrict the Java heap size to 2-8 GB in order to minimize garbage collection pauses.

Is PermGen and method area same?

Method Area is a part of space in the PermGen and it is used to store the class structure and the code for methods and constructors. The biggest disadvantage of PermGen is that it contains a limited size which leads to an OutOfMemoryError.

What is meant by heap size?

The heap size is the amount of memory allocated to objects that are being defined in your Apex code. And Apex code puts in a limit to the total allowed size of the apex heap size. This governor limit is calculated at runtime and depends on how the governor is invoked.