Forcing 64 bit jvm to 32 bit jvm? - jvm

Would anyone please give me ideas about forcing 64 bit jvm to run as 32-bit jvm?
I need to write a jse desktop application for bluetooth connection. For that i need to implement Bluecove jar . It has 32-bit files only. So i included -D32 under VM arguments in eclipse pulsar. But still i am getting the same error that displayed before adding the argument: bluecove_x64.dll missing. I tried with -d32, and it showed me "unrecognized option: d32".
And it seems like i should install a 32-bit jvm that would run on 64-bit os. So, can anyone please tell me what exactly should i install? Java SDK in 32-bit or Eclipse software?
Thanks in advance!

Switching modes is only possible on Solaris. A JVM is either 64bit or 32bit, except on Solaris where both run modes are available in a single JVM.
But anyway, if you don't need more than 4Gig Ram, install the 32bit JVM also on 64bit Systems, because it is 10-15% faster and needs less memory.

First, install a 32-bit JVM. (I suppose this is under Windows).
Then in Eclipse, open the Preferences panel, and go to Java -> Installed JRE's.
Click Search, tell it to search your harddisk.
Wait.
You should now see both your original 64-bit JVM and your new 32-bit JVM in the list. Put the checkmark on the 32-bit JVM instead of the 64-bit JVM. Click OK.
You should now use a 32-bit JVM in Eclipse, which should be compatible with the library you have.

Related

Error when running a 32 bit .dll on a 64 bit JVM Inteliij

I am getting the below error when I try to execute the below line of code in my project. I added a 64 bit JDK to my project properties . I am using Intellij as my IDE
System.loadibrary(smsjavaagentapi)
Fatal Error: Exception from System.loadibrary(smsjavaagentapi) java.lang.unsatisfiedLinkError smsjavaagentapi.dll: Can't load IA 32 bit .dll on an AMD 64-bit platform
I think the problem is that I am using a 64 bit JVM and I am trying to run a 32 bit .dll. I don't have an option to install 32 bit JDK on my machine and add it to my project properties nor I can port the .dll to 64 bit . Is there a work around for this?
There is a limitation at the OS level which prevents a 32-bit shared library being loaded by a 64 bit process, so your options are
modify the OS to allow this (not easy)
migrate the DLL to 64-bit by recompiling it.
install a 32-bit JVM (easier)
download a 32-bit JVM and unpack it without install it. (doesn't require any special permission)
You might find you can get a version of IntelliJ which ships with a 32-bit JVM, or install another program which installs a 32-bit JVM and use just the JVM.

Error while running Jprofile8

I am getting following error while running /tmp/jprofiler8/bin/jpenable
No suitable Java Virtual Machine could be found on your system.
The version of the JVM must be at least 1.6 and at most 1.7.
Please define INSTALL4J_JAVA_HOME to point to a suitable JVM.
You can also try to delete the JVM cache file
I have also set INSTALL4J_JAVA_HOME to point to suitable JVM.
Java version on my machine is 1.4.2.
Can anyone please suggest what might be wrong or missing?
Unfortunately you did not mention details about your environment, so I don't know which Linux distribution you use.
There are some options though:
install a current JRE alongside the installer for JProfiler
As you can't install or update Java, you could provide a JRE in a kind of "portable application" setup. Simply unzip the server jre Oracle provides or (if you are not on an x64 architecture) unzip the jdk you also can download from Oracle.
But if the code you want to profile is limited to your pre-installed Java 1.4 you will run into another problem, because as far as I know Java 1.5 is the minimum JProfiler expects
use a different machine for profiling
Unless your code depends heavily on the environment you run it in you can even take a Windows 8.1 machine and profile the code there. Code that is slow is slow on any operating system. Or make use of a different Linux computer.

JRE Architecture Dependencies (Running on MIPS)

OpenJDK currently does not have support for a JRE on MIPS processors (there's a port in progress, but who knows how long that will take).
I'm trying to understand how the JRE works, and what is standing in the way of using OpenJDK on our embedded system running Linux on a MIPS processor. If I have a custom JVM that is capable of running on MIPS designed to work with OpenJDK (in this case, I'm referring to JamVM 2.0), is there anything else preventing the JRE from running on the MIPS board? Are any other parts of the JRE platform-dependent?
My understanding is that the JRE is (mostly) composed of two units: the virtual machine, which abstracts the hardware and which is platform-dependent, and the collection of Java libraries which run on the virtual machine and which are not platform-dependent.
To be clear, my questions is: aside from the JVM, is any part of the Java Runtime Environment platform-dependent?
"aside from the JVM, is any part of the Java Runtime Environment platform-dependent?"
That depends on where you place the boundary where the VM ends and the JRE begins. I would consider memory management and code execution as 'the VM', everything more specific part of the JRE.
Thats means every binding to the operating system, be it I/O, Graphics etc. is part of the JRE. Thus the JRE has many platform dependent parts; you usually just don't notice them because your code uses their abstractions (e.g. File, Socket, Window).
So when you say "a port to MIPS" it doesn't mean anything without specifying an OS (ok, your link says Linux); a VM ported to a processor architecture by itself does not make a working java environment. It also requires a port of the native parts of the JRE that allow the java program to actually communicate with things outside the VM; thats where the OS platform comes in.
Since Linux is already supported for x64, the MIPS port should be able to reuse most of the JRE to platform bindings from that.

This java instance does not support a 64-bit JVM

I home host a Minecraft server and I just updated Java to update 65, the server worked perfectly before updating but now, it says
"This Java instance does not support a 64-bit JVM. Please install the desired version."
Installing 32-bit Java doesn't help and this also happens when I run my Minecraft client.
I have 64-bit Windows 7 running 64-bit Java 7.
If anybody can help that would be great.
EDIT: Fixed it, apparently I'm just an idiot and had 32-bit installed when I updated java, and since I thought I had 64-bit installed I never thought to re-install it. Sorry for wasting your time
As the author stated, the solution was pretty simple. Bringing it to an answer to help future users
This java instance does not support a 64-bit JVM
This error is associated with your System looking for a Java 64-bit Virtual Machine and not finding any.
To solve it, you must make sure that the 64-bit Java is installed. The problem the OP had was: He assumed he had the 64-bit installed, but he did not.
To download Java, access Java Website
Because you are using 64 bit minecraft client, you are not able to work even with 32 bit JVM.
Kindly install all the things, mincraft server,client, JVM of 32 bit only. You can run it definitely. If still not able to work, let me know with exact error message you are getting.

32 bit JDK on 64 bit Weblogic Server

Is it possible to run an application on a 64 bit Weblogic 10.3.2 Server instance with a 32 bit JDK?
The reason for me to doing this is getting an exceptions while running my program using 64 bit JDK.
UCFWin32JNI.dll: Can't load IA 32-bit .dll on a AMD 64-bit platform
The error is gone when using 32 bit JDK.
If it is possible, then how?
Thanks!
A 32-bit version of a library cannot be loaded and used by a 64-bit JVM, and vice versa.
Moreover, UCFWin32JNI.dll does not appear to be a WebLogic library at all. In fact, it appears to be a library from Documentum. You ought to be looking for a 64-bit version of that library (if it is available) as it appears to be a 32-bit version going by the name and the error message produced. Finally, you'll need to place the 64-bit version in one of the directories constituting java.library.path.
No problems at all running a 32bit JVM on a 64bit platform. In fact, for some applications it can actually be more efficient, due to the fact that certain data types are innately larger on a 64bit JVM (ints I think are an example of this from memory)
A 64bit JVM provides all sorts of advantages for an application requiring access to a larger heap, but there's no harm at all in running a 32bit JVM.