I just had an interview, and I was asked to create a memory leak with Java.
Needless to say, I felt pretty dumb having no clue on how to eve
Probably one of the simplest examples of a potential memory leak, and how to avoid it, is the implementation of ArrayList.remove(int):
public E remove(int index) {
RangeCheck(index);
modCount++;
E oldValue = (E) elementData[index];
int numMoved = size - index - 1;
if (numMoved > 0)
System.arraycopy(elementData, index + 1, elementData, index,
numMoved);
elementData[--size] = null; // (!) Let gc do its work
return oldValue;
}
If you were implementing it yourself, would you have thought to clear the array element that is no longer used (elementData[--size] = null
)? That reference might keep a huge object alive ...