You can just leak memory by leaving references to it around. Sometimes called memory abandonment.

With some systems you can pin it and forget to unpin it.

Very good explanation. I always wondered what is the equivalent of memory leak in a garbage collected language. Are there any tools for this?

Well, there’s the one in the article. Usually each GC implementation comes with its own tools.

You can watch process memory in general and see if keeps going up; if it does, it’s someone’s fault.

My question exactly.