java - Heap vs Stack vs Perm Space

Question

• What are the differences between the Java memory spaces (Perm Space, Space Stack, Heap Space)?
• When does the JVM use one or another?
• If I use Scala/Groovy/etc., are there differences?

Answer 1

Simply

• Heap space: All live objects are allocated here.
• Stack space: Stores references to the object for variable in method call or variable instantiation.
• Perm space: Stores loaded classes information

For example:

Student std = new Student();

after executing the line above memory status will be like this.

• Heap: stores "new Student()"
• Stack: stores information about "std"
• Perm Space: stores information about Student class