What is the memoy size of a Java object array after it has been created?
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Published on 2012-11-13T04:54:40Z
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This probably doesn't even need asking, but I want to make sure I'm right on this. When you create an array of any object in Java like so:
Object[] objArr = new Object[10];
The variable objArr is located in stack memory, and it points to a location in the heap where the array object is located. The size of that array in the heap is equal to a 12 byte object header + 4 (or 8, depending on the reference size) bytes * the number of entries in the array. Is this accurate?
My question, then, is as follows. Since the array above is empty, does it take up 12 + 4*10 = 52 bytes of memory in the heap immediately after the execution of that line of code? Or does the JVM wait until you start putting things into the array before it instantiates it? Do the null references in the array take up space?
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