How to run 32-bit Java on Mac OSX 10.7 Lion
Solution 1
I found out now, that the 32-bit JVM can be explicitly launched using the -d32 switch.
On my machine, "java -version -d32" says:
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03-383-11A511c)
Java HotSpot(TM) Client VM (build 20.1-b02-383, mixed mode)
and although it doesn't say so, it is a 32-bit JVM.
Solution 2
The latest versions of Java 64-bit have -XX:+UseCompressedOops on by default (if your heap is less than 32 GB). This means 32-bit references are used in any case. The objects are still slightly bigger (4 bytes more overhead)
This article compares 32-bit, 64-bit with UseCompressedOops Java: How much memory do different arrays and collections consume
In terms of performance, I have found it to be 5-10% depending on what you are doing. If you are using a lot of long
values it will be faster to use 64-bit.
Solution 3
Go into the "Java Preferences" App and drag java 32 bit to the top of the list.
Solution 4
Try the below steps:
- Open terminal and go to /System/Library/Frameworks/JavaVM.framework/Versions/
- Type ls -l to list all available Java versions
- Enter sudo ln -fhsv CurrentJDK
Reference: Changing Java Version
Solution 5
in /System/Library/Frameworks/JavaVM.framework/Versions I found version 1.6 installed and changed the path for java,javac to point to /System/Library/Frameworks/JavaVM.framework/Versions/1.6/home using environment alias rather than the default link found in /usr/bin/
Ulrik
Updated on July 09, 2022Comments
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Ulrik almost 2 years
From my experience with Windows 7 (64-bit) and Java, a 32-bit JRE uses less memory and runs significantly faster than a 64-bit JRE (provided you don't need or benefit from having a lot of memory). I imagine the same thing is true for Mac OSX (and other platforms) as well.
I am currently running OSX Lion (v10.7), and I have installed the standard Java app. Under Java Preferences, I see "Java SE 6" from "Apple Inc." for both CPU-types "32-bit" and "64-bit" version "1.6.0_26-b03-383". I have changed the preferred order to put the 32-bit version on top of the 64-bit version, hoping that this would make the 32-bit version default.
But "java -version" still says:
java version "1.6.0_26" Java(TM) SE Runtime Environment (build 1.6.0_26-b03-383-11A511c) Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02-383, mixed mode)
Is it possible to use the 32-bit version by default? And how?
Also, does anyone have experiences / comparative measurements regarding speed and memory efficiency between the 32/64-bit versions?
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Ulrik almost 13 yearsThis is somewhat useful info, but how do I start the 32-bit JVM? The referred article compares 32- and 64-bit JVMs (although perhaps on a different platform).
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Vishy almost 13 yearsIn UNIX, I would open a shell and use the full path name to run the program I want (works for just about any program). Or I would change the default PATH to include the
bin
directory in Windows or Unix to use the 32-bit version (again nothing specific to Java) -
Ulrik almost 13 yearsIn Windows or UNIX this is trivial, I know... All you need to know is the install location of the JRE for finding the java binary and perhaps setting a proper JAVA_HOME environment variable. On a Mac, the Java installation is really obscure, and I have not been able to locate the 32-bit installation. BUT I think the information shown in the Java Preferences GUI implies that a 32-bit version is present somehow... somewhere...
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Ulrik over 12 yearsAs I described, that is what I already tried - without seeing any difference.
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Kelvin almost 12 years+1 worked perfectly. I ran a java app and it showed up in Activity Monitor as Kind:
Intel
instead ofIntel (64 bit)
. For some reason thearch
command doesn't have any affect on java.