QOTD: Java Thread vs. Java Heap Space
DZone's Guide to
QOTD: Java Thread vs. Java Heap Space
Join the DZone community and get the full member experience.
Join For FreeDownload Microservices for Java Developers: A hands-on introduction to frameworks and containers. Brought to you in partnership with Red Hat.
The following question is quite common and is related to
OutOfMemoryError: unable to create new native thread problems during the JVM thread creation process and the JVM thread capacity.
This is also a typical interview question I ask to new technical candidates (senior role). I recommend that you attempt to provide your own response before looking at the answer.
This is also a typical interview question I ask to new technical candidates (senior role). I recommend that you attempt to provide your own response before looking at the answer.
Question:
Why can’t you increase the JVM thread capacity (total # of threads) by expanding the Java heap space capacity via -Xmx?
Answer:
The Java thread creation process requires native memory to be available for the JVM process. Expanding the Java heap space via the –Xmx argument will actually reduce your Java thread capacity since this memory will be “stolen” from the native memory space.
- For a 32-bit JVM, the Java heap space is in a race with the native heap, including the thread capacity
- For a 64-bit JVM, the thread capacity will mainly depend of your OS physical & virtual memory availability along with your current OS process related tuning parameters
In order to better understand this limitation, I now propose to you the following video tutorial.
Download Building Reactive Microservices in Java: Asynchronous and Event-Based Application Design. Brought to you in partnership with Red Hat.
Like This Article? Read More From DZone
Topics:
Published at DZone with permission of Pierre - Hugues Charbonneau , DZone MVB. See the original article here.
Opinions expressed by DZone contributors are their own.
{{ parent.title || parent.header.title}}
{{ parent.tldr }}
{{ parent.linkDescription }}
{{ parent.urlSource.name }}