Do Java primitives go on the Stack or the Heap?

by

Primitives defined locally would be on the stack. However if a primitive were defined as part of an instance of an object, that primitive would be on the heap.

public class Test {
    private static class HeapClass {
        public int y; // When an instance of HeapClass is allocated, this will be on the heap.
    }
    public static void main(String[] args) {
        int x=1; // This is on the stack.
    }
}

With regards to the update:

Objects do not have their own stack. In my example, int y would actually be part of each instance of HeapClass. Whenever an instance of HeapClass is allocated (e.g. new Test.HeapClass()), all member variables of HeapClass are added to the heap. Thus, since instances of HeapClass are being allocated on the heap, int y would be on the heap as part of an instance of HeapClass.

However, all primitive variables declared in the body of any method would be on the stack.

As you can see in the above example, int x is on the stack because it is declared in a method body–not as a member of a class.

More Related Contents:

  1. Is a Java array of primitives stored in stack or heap?
  2. How to specify more than 64 mb memory for an application?
  3. Object creation on Heap
  4. How to deal with “java.lang.OutOfMemoryError: Java heap space” error?
  5. Error java.lang.OutOfMemoryError: GC overhead limit exceeded
  6. Increase heap size in Java
  7. How is the default max Java heap size determined?
  8. Could not reserve enough space for object heap
  9. Using HeapDumpOnOutOfMemoryError parameter for heap dump for JBoss
  10. java.lang.OutOfMemoryError: GC overhead limit exceeded [duplicate]
  11. java.lang.OutOfMemoryError: Java heap space
  12. Java heap terminology: young, old and permanent generations?
  13. Java 7 (JDK 7) garbage collection and documentation on G1
  14. Is there a way to lower Java heap when not in use?
  15. Setting JVM heap size at runtime
  16. increase the java heap size permanently?
  17. How do I analyze a .hprof file?
  18. Difference between “on-heap” and “off-heap”
  19. Heap space out of memory
  20. How does the JVM ensure that System.identityHashCode() will never change?
  21. Java Refuses to Start – Could not reserve enough space for object heap
  22. Understanding max JVM heap size – 32bit vs 64bit
  23. Encourage the JVM to GC rather than grow the heap?
  24. How to find the number of objects in the heap
  25. PySpark: java.lang.OutofMemoryError: Java heap space
  26. Why a sawtooth shaped graph?
  27. java.lang.OutOfMemoryError: Java heap space with NetBeans
  28. how to increase java heap memory permanently?
  29. How to increase java heap size programmatically
  30. how to choose the jvm heap size?

Leave a Comment