File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Java in General and the fly likes Difference between Runtime.gc() and System.gc() Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login

Win a copy of REST with Spring (video course) this week in the Spring forum!
JavaRanch » Java Forums » Java » Java in General
Bookmark "Difference between Runtime.gc() and System.gc()" Watch "Difference between Runtime.gc() and System.gc()" New topic

Difference between Runtime.gc() and System.gc()

vitthal wable

Joined: Sep 09, 2006
Posts: 16
Can You please tell me the difference between Runtime.gc() and System.gc()
Ta Ri Ki Sun
Ranch Hand

Joined: Mar 26, 2002
Posts: 442
No difference at all.

From javadoc :
The call <code>System.gc()</code> is effectively equivalent to the call: Runtime.getRuntime().gc()
Peter Chase
Ranch Hand

Joined: Oct 30, 2001
Posts: 1970
The difference is that you shouldn't call either of them ;-)

Betty Rubble? Well, I would go with Betty... but I'd be thinking of Wilma.
Marcus Hathaway
Ranch Hand

Joined: Jun 07, 2005
Posts: 89
Hi Peter, why shouldn't you call them?

ps....thats not a loaded question, i'm interested to learn more
Robert Hill
Ranch Hand

Joined: Feb 24, 2006
Posts: 94
For starters calling .gc() does not guarantee that the gc will run at that time. It makes a "best effort" attempt and cleaning unneeded objects.

The second reason is that the gc is a resource hog. Adding the call in your code adds overhead and isn't even necessary. The GC does its job well.

The amount of times that a developer will actually need to mess with the gc or call it directly are rare.
I agree. Here's the link:
subject: Difference between Runtime.gc() and System.gc()
It's not a secret anymore!