Heap vs. Stack memory

Heap vs. Stack memory

    

CONTENTS

• Objects are always stored in Heap 
• Reference variables to objects and primitive variables are stored in Stack memory

USABILITY

• Heap memory is used globally by all components of the application
• Stack memory is used only by one thread of execution.

LIFE

• Heap memory lives from the start till the end of application execution.
• Stack memory is short-lived.

SIZE

• Stack memory size is very less when compared to Heap memory.

ERRORS   

• When stack memory is full, JRE throws java.lang.StackOverFlowError
• If heap memory is full, it throws java.lang.OutOfMemoryError

SPEED

• Stack memory is very fast when compared to heap memory due to simplicity in memory allocation (LIFO).

JVM OPTIONS    

• Use -Xms and -Xmx JVM option to define the startup size and maximum size of heap memory.
• Use -Xss to define the stack memory size.

MEMORY MANAGEMENT

• Heap memory is divided into Young-Generation, Old-Generation etc.
• Memory management in stack is done in LIFO manner