Why does appending "" to a String save memory?
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Published on 2010-01-27T14:52:06Z
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2010/04/29
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I used a variable with a lot of data in it, say String data.
I wanted to use a small part of this string in the following way:
this.smallpart = data.substring(12,18);
After some hours of debugging (with a memory visualizer) I found out that the objects field smallpart remembered all the data from data, although it only contained the substring.
When I changed the code into:
this.smallpart = data.substring(12,18)+"";
..the problem was solved! Now my application uses very little memory now!
How is that possible? Can anyone explain this? I think this.smallpart kept referencing towards data, but why?
UPDATE: How can I clear the big String then? Will data = new String(data.substring(0,100)) do the thing?
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