Determining RAM size using Java

Hi,
Apologies in advance if this seems to be an oft-repeated topic. I just wanted to confirm if I am missing something or not.
I am trying to find the total amount of RAM available to the OS and am using the java management API to do it (I am using JDK 1.6 update 7):
import java.lang.management.ManagementFactory;
import com.sun.management.OperatingSystemMXBean;
public class Mem{
     public static void main(String[] args){
          OperatingSystemMXBean osb = (com.sun.management.OperatingSystemMXBean)ManagementFactory.getOperatingSystemMXBean();
          System.out.println(osb.getTotalPhysicalMemorySize());
}This code seems to return the correct value of total RAM on Linux. On Windows, however, I get some random value. I believe it could be because of this bug: [http://bugs.sun.com/bugdatabase/view_bug.do;jsessionid=132bbb6b3cbd535627637e96a07c?bug_id=6628662|http://bugs.sun.com/bugdatabase/view_bug.do;jsessionid=132bbb6b3cbd535627637e96a07c?bug_id=6628662] So I doubt I can use this approach on Windows.
An alternate way would be to call OS specific commands from within Java, parse the results I receive and use them. I would like to keep that as the last resort. I want to avoid JNI too.
My question is, is there any other way to retrieve the information? Are there lightweight third-party tools which can be integrated into my java code?
Any input will be greatly appreciated.
Thank you!

I need this info for a "setup" program which allows the end-user to choose how much max heap memory they want to allocate for their application. I don't want to display values which are beyond what is physically available in the system.Ok. IMHO this is not a great use of your time. First of all, total RAM is not nearly as important as total RAM - memory manager - OS. Second of all, system memory is more than just RAM. Virtual memory allows you to have much more in memory than your RAM.
IMHO you should leave this to the user to performance tune their own machine.

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To check RAM size via java program

Hi,
Please let me know how to find the RAM size of a machine using java program.
Thanks & Regards,
Nasrin.N

Hi,
I've done that for disk space with JNative, take a look at http://sourceforge.net/project/screenshots.php?group_id=156421
I think it's easy to implement it for RAM.
--Marc (http://jnative.sf.net)

Problem with too small page size using Java 2D Printing API.

Hello,
I have problem with resolution of printer using Java 2D Printing API. Despite my printer has 600 x 600 DPI, inside java.awt.print.Printable.print(Graphics, PageFormat, int) I receive page format with 600 x 840 page size.
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600 x 840 is a Point value; Point is defined as 1/72nd of an inch. Printers do have much higher DPI than this, but I believe that this DPI has to do with richness of the printed image, not an actual ability to color with that level of resolution. You might want to try calling zoom on your Graphics2D object. Otherwise, I don't know what else you can try.

Problem increasing heap size using Java Control Panel

I am running a web-based bioinformatics package which uses a Java applet as the client application. It mostly works fine, but some large clustering processes don't complete, they just cycle endlessly. The user manual advises increasing heap space "by entering the following command in the Java Control Panel or Java Plug-in dialog: -Xms128M -Xmx256M." I can open the Java Control Panel OK and enter the necessary command in the Java Runtime Parameters box, but after clicking OK then Apply, the Runtime Parameters box is empty again and there is no increase in the heap size allocation. In other words, the change doesn't take effect.
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The failure to retain the parameters is a bug, per hdong in this [Java,net thread|http://forums.java.net/jive/thread.jspa?threadID=44540&tstart=0] dated August 14
"I did a little more research and found out that the problem is only with "-rc" or "-beta" versions of plugin. When 1.6.0_10 is finally released, the version string will be "1.6.0_10". Plugin works fine to set/get jvm parameters when version string is "1.6.0_10".
I am surprised that this issue was not discovered earlier. It was probably because the internal test binary use "1.6.0_10" as version string.
Yeah, it is a bug that will affect many manny developers. It will be fixed as soon as possible."

File size (using java.io.File)

Hello all,
When I want to create an app to be used as file browser, I should like to know the size of a file in a directory. The java.io.File class gives me quite some functionality, but not the functionality to display the file size.
Does anyone know of a default class that has the functionality to display the file size?
When no such class exists, I should need to develop it myself. From the top of my head it should be something like this:
int size = 0;
int aChar = 0;
FileReader reader = new FileReader (theFile);
while (reader.ready() )
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size++;
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Looking forward to your answer
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Hi, I'm having the exact same problem, except that I'm doing a fax system so I can't copy a file while the file is still open. So to check to see if the file is open I have to check the file size in bytes then wait a second and check the file size again. If the file sizes differ then I have to check the next file otherwise I can copy the file. I had a look at the length() method but that will only return the actual length of the file name, not the size of the contents of the file which I need, can anyone please help? Say the file name is 16 ad an a or anything to the file name, if you the call the length() method again it will return 17.

Determining password expiry using java + ADLDS

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You may alter your profile beforehand:
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How to change the font size of the string by using java?

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Text is displayed in some kind of text component - JTextField, JTextArea, JTextPane....To change the font of the text you change the font associated with the text component:
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How to increase heap size in java code, not using "java -Xms64m "

Im writing a java programme for loading the german dictionary. my dictionary is very huge(around 300000+ words).
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I found one solution to increase the heap size, but i want to increase the heap size in java programmer itself, not outside jar file. so i could not use "-Xms64m" option of jvm.
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sunlover1984 wrote:
Im writing a java programme for loading the german dictionary. my dictionary is very huge(around 300000+ words).
while loading the dictioanry im getting error "OutOfMemoryError" .
I found one solution to increase the heap size, but i want to increase the heap size in java programmer itself, not outside jar file. so i could not use "-Xms64m" option of jvm.
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How to determine the presence of adobe pdf reader using java/J2EE?

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I am in the software, where can I find it?
On Tue, Jan 27, 2015 at 9:59 AM, Sara.Forsberg <[email protected]>

4gb file size limitation using java.io.* package in java stored procedure

Does anyone know about file size limitations when using java.io.* package inside java stored procedures. I have some java stored procedures that read and write to files. They error out when run as a java stored procedure within oracle on files over 4gb. I have no problems with these procedures when I test them outside of oracle.

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How Can I Determine the Size of the 'My Documents' Folder for every user on a local machine using VBScript?

Hello,
I am at my wits end into this. Either I am doing it the wrong way or it is not possible.
Let me explain. I need a vb script for the following scenario:
1. The script is to run on multiple Windows 7 machines (32-Bit & 64-Bit alike).
2. These are shared workstation i.e. different users login to these machines from time to time.
3. The objective of this script is to traverse through each User Profile folder and get the size of the 'My Documents' folder within each User Profile folder. This information is to be written to a
.CSV file located at C:\Temp directory on the machine.
4. This script would be pushed to all workstations from SCCM. It would be configured to execute with
System Rights
I tried the script detailed at:
http://blogs.technet.com/b/heyscriptingguy/archive/2005/03/31/how-can-i-determine-the-size-of-the-my-documents-folder.aspx
Const MY_DOCUMENTS = &H5&
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Set objShell = CreateObject("Shell.Application")
Set objFolder = objShell.Namespace(MY_DOCUMENTS)
Set objFolderItem = objFolder.Self
strPath = objFolderItem.Path
Set objFolder = objFSO.GetFolder(strPath)
Wscript.Echo objFolder.Size
The Wscript.Echo objFolder.Size command in the script at the above mentioned link returned the value as
'0' (zero) for the current logged on user. Although the actual size was like 30 MB or so.
I then tried the script at:
http://www.experts-exchange.com/Programming/Languages/Visual_Basic/VB_Script/Q_27869829.html
This script returns the correct value but only for the current logged-on user.
Const blnShowErrors = False
' Set up filesystem object for usage
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objShell = CreateObject("WScript.Shell")
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Wscript.Echo "MyDocuments : " & FormatSize(FindFiles(objFSO.GetFolder(objShell.SpecialFolders("MyDocuments"))))
' Recursively tally the size of all files under a folder
' Protect against folders or files that are not accessible
Function FindFiles(objFolder)
On Error Resume Next
' List files
For Each objFile In objFolder.Files
On Error Resume Next
If Err.Number <> 0 Then ShowError "FindFiles:01", objFolder.Path
On Error Resume Next
FindFiles = FindFiles + objFile.Size
If Err.Number <> 0 Then ShowError "FindFiles:02", objFile.Path
Next
If Err.Number = 0 Then
' Recursively drill down into subfolder
For Each objSubFolder In objFolder.SubFolders
On Error Resume Next
If Err.Number <> 0 Then ShowError "FindFiles:04", objFolder.Path
FindFiles = FindFiles + FindFiles(objSubFolder)
If Err.Number <> 0 Then ShowError "FindFiles:05", objSubFolder.Path
Next
Else
ShowError "FindFiles:03", objFolder.Path
End If
End Function
' Function to format a number into typical size scales
Function FormatSize(iSize)
aLabel = Array("bytes", "KB", "MB", "GB", "TB")
For i = 0 to 4
If iSize > 1024 Then iSize = iSize / 1024 Else Exit For End If
Next
FormatSize = Round(iSize, 2) & " " & aLabel(i)
End Function
Sub ShowError(strLocation, strMessage)
If blnShowErrors Then
WScript.StdErr.WriteLine "==> ERROR at [" & strLocation & "]"
WScript.StdErr.WriteLine " Number:[" & Err.Number & "], Source:[" & Err.Source & "], Desc:[" & Err.Description & "]"
WScript.StdErr.WriteLine " " & strMessage
Err.Clear
End If
End Sub
The only part pending, is to achieve this for the 'My Documents' folder within each User Profile folder.
Is this possible?
Please help.

Here are a bunch of scripts to get folder size under all circumstances. Take your pick.
https://gallery.technet.microsoft.com/scriptcenter/site/search?query=get%20folder%20size&f%5B0%5D.Value=get%20folder%20size&f%5B0%5D.Type=SearchText&ac=2
¯\_(ツ)_/¯

How do you reference a Formular Object on a Crystal Report using Java

Hi all,
I am trying to reference an object on my report which contains a Formula field.
I have read the following 2 threads, but they refer to textObjects:
[How do you reference a textObject on a Crystal report using Java|Re: How do you reference a textObject on a Crystal report using Java?]
[Changing the text of ITextObject programatically|Re: Changing the text of ITextObject programatically]
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Edited by: Darren Jackson on Dec 16, 2009 7:29 PM
Forgot to add am using CR4Ev2 SP3

Right I have made some headway.
Firstly, Im an idiot. I was making changes and setting up test fields on my report, but then when running the app, I had it looking at
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Cheers

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Hello,
I need to get the size of an inputstream. In fact, I am working with java.nio.channels and need to tranfer a file from within a Jar to the FileSystem.
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advanced Thanx
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In general the "size of an InputStream" is a meaningless concept. It's possible to have an InputStream that never terminates. So if you can't get a size from whatever you're reading from, you're out of luck.
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Application started using Java Web Start doesn't launch the first time

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I signed my application and make use of all security settings.
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<?xml version="1.0" encoding="utf-8"?>
<jnlp spec="1.0+"
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<menu submenu="Bloom"/>
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<application-desc main-class="ca.antaki.www.bloom.gui.Bloom" />
</jnlp>Here is the link for my application http://antaki.ca/bloom/Bloom.jnlp
The first time the application is installed using a link on the browser it's downloaded then the certificate dialog is shown, after that I check the checkbox to accept the certificate permanently. The application doesn't load, it only loads the second time although I see it in the task manager. If I don't accept the certificate permanently it does load. This happens on both Firefox 2 and IE 7. I enabled the console and logging but nothing shows up there.That's really a weird problem, I wonder if Java Web Start is a viable deployment option, it does have great capabilities such as autoupdate but still seems to have important bugs.
Does anyone have any clue about what is going on.
The problem doesn't occur on Ubuntu 7.10.
Thanks,
Carl Antaki

>
You were right my XML file was not correct. I still couldn't find a valid JNLP validator. Sun has to provide that.>No they don't (have to supply a validator for their own document type, though it makes sense to do so), but yes they do (provide a tool that validates XML against schemas). Java can validate XML against a DTD or XSD.
Check these two threads (and chase the links) for more details.
JNLP xsd schema
<http://groups.google.com.au/group/comp.lang.java.programmer/browse_thread/thread/c6f65bf1df5f105d/30c6b7e2dc342dc4>
Validate XML against DTD? XSD OK. SSCCE.
<http://groups.google.com.au/group/comp.lang.java.programmer/browse_thread/thread/5b997a1edb765b11/e831f3066eb4aa38>
Look especially for the posts by Piotr Kobzda.
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Problem with CORBA application deployed using Java Web Start 1_6_0.

Java Web Start fans and experts:
We have been using Java Web Start to deploy the client side of a CORBA-based application since the inception of Java Web Start ... including Java Web Start 1.0 right up through the present.
With Java Web Start 1_6_0, we see evidence that Web Start is "tinkering with" the IOR that CORBA uses to communicate. In all previous versions of Java Web Start, independent of the JRE which the application uses, the stringified IOR have been the same size regardless of whether the application is deployed locally or via Java Web Start. With Java Web Start 1_6_0, the stringified IOR is much longer than the "real" IOR (again, regardless of the JRE used by the application itself). To me this smells like a bug in Java Web Start 1_6_0. Has anyone else observed this behavior?
Here are some specifics .... I've run the same client application with various JREs both with and without Java Web Start as the deployment mechanism. The application was compiled and runs against servers that are running JDK 1_5_0_09.
Here is the summary of my results from a Linux box running various JREs, various versions of Java Web Start, and also running as a non-JWS deployed application. I've listed the length of the stringified IOR in each case.
JRE 1.5.0 non-JWS client: stringified IOR length = 344
JRE 1.6.0 non-JWS client: stringified IOR length = 344 ... this, I think, excludes the JRE as the cause of these problems.
Java WS 1.5.0, JRE 1.5.0 JWS client: stringified IOR length = 344
Java WS 1.5.0, JRE 1.6.0 JWS client: stringified IOR length = 344
Java WS 1.6.0, JRE 1.6.0 JWS client: stringified IOR length = 1568
Java WS 1.6.0, JRE 1.5.0 JWS cleint: stringified IOR length = 1568
In all cases, the stringified IOR length is determined by the service receiving the message and is always running JRE 1_5_9_09 and is
always the same 344 characters in length UNLESS it was deployed
using Java Web Start 1_6_0, in which case it in nearly 5 times as big!
To me, it sure looks as if there is a problem with Java Web Start 1_6_0 to be adding so much to the stringified IOR. Note: it's hard to tell how different the underlying IOR is in the JWS 1_6_0 case because, unlike most other ORBs, the Sun ORB doesn't have a tool to extract the IOR into a human readable structure. However, I can think of no good reason why the identical application deployed using Java Web Start 1_6_0 should have a stringified IOR length that is different than that of the same application deployed in non-JWS form or should differ from the behavior seen in all previous releases of Java Web Start.
Any clues or suggestions? Has anyone else observed this behavior?
Thanks,
John

Hi.
I got a different problem. My Corba application works in JRE 1.6, but doesn't works in JRE 1.5.X. I got an unexpected error and my console shows:
getSubjectX500Principal NoSuchMethodError: java.lang NoSuchMethodError
#### Java Web Start Error:
#### null
Can you help me?

Determining RAM size using Java

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