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javaarraysmemory-managementgarbage-collectionheap-memory

Deleting Part of An Array in Java to Free Memory on Heap

I am implementing a dynamic programming algorithm for the knapsack problem in Java. I declare the array and then initialize its size to be [number of objects][capacity of knapsack].

When my number of objects or my capacity gets too large, I get a memory error because I run out of space on the heap. My questions is: If I delete rows from my double array as I go along, will Java free the memory as I delete? Or does Java reserve that memory space for the size of the array I originally created? If it's the latter, is there a way to manually free the memory in Java?

Thanks for your Help!

Solution

  • The short answer is "yes" - if you're using arrays like this:

    private void foo () {
  int[][] bar = new int[10][10];
  bar[1] = null;  
  //at this point, the array that was in bar[1] is eligible for garbage collection
  //unless someone else has a reference to it
}