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// (jEdit options) :folding=explicit:collapseFolds=1:
import java.io.*;
import java.text.*;
import java.util.*;
import javax.swing.*;
/**
* <code>JComboBoxLeak</code> shows a memory leak caused by
* removeAllItems() in JComboBox.
*
* <br>Begun on Tue Feb 18 10:33:35 EST 2003
*/
public class JComboBoxLeak //extends ... implements ...
{
static DecimalFormat df = new DecimalFormat("#,##0");
//##################################################################################################
/** I use this from JDB for tracking down memory leaks */
public static String showMem()
{
Runtime runtime = Runtime.getRuntime();
int i, total0 = 0, free0 = 0, total1 = 0, free1 = 0, used; // in kilobytes
// Take up to 10 tries at garbage collection
for(i = 0; i < 10; i++)
{
total1 = (int)(runtime.totalMemory() >> 10);
free1 = (int)(runtime.freeMemory() >> 10);
if(total1 == total0 && free1 == free0) break;
else
{
System.gc();
//try { Thread.sleep(500); } catch(InterruptedException ex) {}
total0 = total1;
free0 = free1;
}
}
used = total1 - free1;
return df.format(used)+"kb / "+df.format(total1)+"kb";
}
//##################################################################################################
public static void main(String[] args)
{
JComboBox box = new JComboBox();
System.out.println("Before creating bigObj: "+showMem());
int[] bigObj = new int[10000000]; // ~ 40MB
System.out.println("After creating bigObj: "+showMem());
box.addItem(bigObj);
bigObj = null;
System.out.println("After adding bigObj: "+showMem());
box.removeAllItems();
System.out.println("After calling removeAllElements(): "+showMem());
int[] smallObj = new int[1000000]; // ~ 4MB
System.out.println("After creating smallObj: "+showMem());
box.addItem(smallObj);
smallObj = null;
System.out.println("After adding smallObj: "+showMem());
box.removeAllItems();
System.out.println("After calling removeAllElements(): "+showMem());
box.setModel(new DefaultComboBoxModel());
System.out.println("After replacing data model: "+showMem());
}
}//class
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