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Java-wrapped Matlab function: `java` can't load/find `main` sample invoker class

Java-wrapped Matlab function: java can't load/find main sample invoker class
I'm following a MATLAB example of wrapping a MATLAB function in a Java interface. The sample driver (i.e., invoker of the wrapped function) compiles without errors or any messages, but java says that it can't find/load the main class, i.e., the sample driver.
The MATLAB function to be wrapped is exactly as it is on the web page (and in fact, it comes with the MATLAB installation):
" makesqr.m
"----------
function y = makesqr(x)
y = magic(x);
The sample invoker is extremely simple:
" makesqrSample1.m
"-----------------
% Sample script to demonstrate execution of function y = makesqr(x)
x = 3; % Initialize x here
y = makesqr(x);
Everything is exactly as shown in the webpage. I get all the files described in this file summary.
Things start to depart from expected in the "Install and Implement MATLAB Generated Java Application" section. Step 3 refers to a sample invoker getmagic.java instead of the makesqrSample1.java (automagically generated by MATLAB from makesqrSample1.m above). I assume that this is a typo.
With makesqr.jar and makesqrSample1.java in the same (current working) directory, the following compilation issues no messages or errors.
javac -cp \
"makesqr.jar;C:\Program Files\MATLAB\R2019a\toolbox\javabuilder\jar\javabuilder.jar" \
makesqrSample1.java
This creates makesqrSample1.class in the same folder. Here is the error from execution:
java -cp \
"makesqr.jar;C:\Program Files\MATLAB\R2019a\toolbox\javabuilder\jar\javabuilder.jar" \
makesqrSample1
Error: Could not find or load main class makesqrSample1
I checked that the that auto-generated makesqrSample1.java does have main (see ANNEX below).
This is a minimal example, following the documentation faithfully. What is causing main to not be recognized?
CONTEXTUAL DETAILS
Version output (select details):
MATLAB Version: 9.6.0.1072779 (R2019a)
Operating System: Microsoft Windows 10 Pro Version 10.0 (Build 18362)
Java Version: Java 1.8.0_181-b13 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode
MATLAB Compiler Version 7.0.1 (R2019a)
MATLAB Compiler SDK Version 6.6.1 (R2019a)
Installed JDK:
C:\Program Files\AdoptOpenJDK\jdk-8.0.265.01-hotspot
Since I have MATLAB installed, I didn't get the MATLAB Runtime (and from past experience, it has never been clear how/whether the Runtime is being used when MATLAB is installed). The the problem is occurring right up front finding/loading main.
ANNEX: AUTO-GENERATED makesqrSample1.java
import com.mathworks.toolbox.javabuilder.*;
import makesqr.Class1;
/**
*
* Sample driver code that is integrated with a compiled MATLAB function
* generated by MATLAB Compiler SDK.
*
* Refer to the MATLAB Compiler SDK documentation for more
* information.
*
* #see com.mathworks.toolbox.javabuilder.MWArray
*
*/
public class makesqrSample1 {
private static Class1 class1Instance;
private static void setup() throws MWException {
class1Instance = new Class1();
}
/**
* Sample code for {#link Class1#makesqr(int, Object...)}.
*/
public static void makesqrExample() {
MWArray xIn = null;
MWNumericArray yOut = null;
Object[] results = null;
try {
double xInData = 3.0;
xIn = new MWNumericArray(xInData, MWClassID.DOUBLE);
results = class1Instance.makesqr(1, xIn);
if (results[0] instanceof MWNumericArray) {
yOut = (MWNumericArray) results[0];
}
System.out.println(yOut);
} catch (Exception e) {
e.printStackTrace();
} finally {
// Dispose of native resources
MWArray.disposeArray(xIn);
MWArray.disposeArray(results);
}
}
public static void main(String[] args) {
try {
setup();
} catch (Exception e) {
e.printStackTrace();
System.exit(1);
}
try {
makesqrExample();
} catch (Exception e) {
e.printStackTrace();
System.exit(1);
} finally {
// Dispose of native resources
class1Instance.dispose();
}
}
}

This answer is definitely for the Java newbies. The class path for java needs to include the directory . of the newly-compiled makesqrSample1.class:
java -cp \
"makesqr.jar;C:\Program Files\MATLAB\R2019a\toolbox\javabuilder\jar\javabuilder.jar;." \
makesqrSample1
Running C:\cygwin64\tmp\User.Name\mcrCache9.6\makesq0\makesqr\startup
8 1 6
3 5 7
4 9 2
What I find odd is that this java is a Windows installation, yet it seems to recognize that I'm invoking it from Cygwin, and it creates a working folder in C:\cygwin64\tmp\User.Name.

Execute an AWS command in eclipse

I execute an EC2 command through eclipse like:
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
String spot = "aws ec2 describe-spot-price-history --instance-types"
+ " m3.medium --product-description \"Linux/UNIX (Amazon VPC)\"";
System.out.println(spot);
Runtime runtime = Runtime.getRuntime();
final Process process = runtime.exec(spot);
//********************
InputStreamReader isr = new InputStreamReader(process.getInputStream());
BufferedReader buff = new BufferedReader (isr);
String line;
while((line = buff.readLine()) != null)
System.out.print(line);
}
The result in eclipse console is:
aws ec2 describe-spot-price-history --instance-types m3.medium --product-description "Linux/UNIX (Amazon VPC)"
{ "SpotPriceHistory": []}
However, when I execute the same command (aws ec2 describe-spot-price-history --instance-types m3.medium --product-description "Linux/UNIX (Amazon VPC)") in shell I obtain a different result.
"Timestamp": "2018-09-07T17:52:48.000Z",
"AvailabilityZone": "us-east-1f",
"InstanceType": "m3.medium",
"ProductDescription": "Linux/UNIX",
"SpotPrice": "0.046700"
},
{
"Timestamp": "2018-09-07T17:52:48.000Z",
"AvailabilityZone": "us-east-1a",
"InstanceType": "m3.medium",
"ProductDescription": "Linux/UNIX",
"SpotPrice": "0.047000"
}
My question is: How can obtain in eclipse console the same result as in shell console ?

It looks like you are not getting the expected output because you are passing a console command through your Java code which is not getting parsed properly, and you are not utilizing the AWS SDKs for Java instead.
To get the expected output in your Eclipse console, you could utilize the DescribeSpotPriceHistory Java SDK API call in your code[1]. An example code snippet for this API call according to the documentation is as follows:
AmazonEC2 client = AmazonEC2ClientBuilder.standard().build();
DescribeSpotPriceHistoryRequest request = new DescribeSpotPriceHistoryRequest().withEndTime(new Date("2014-01-06T08:09:10"))
.withInstanceTypes("m1.xlarge").withProductDescriptions("Linux/UNIX (Amazon VPC)").withStartTime(new Date("2014-01-06T07:08:09"));
DescribeSpotPriceHistoryResult response = client.describeSpotPriceHistory(request);
Also, you could look into this website containing Java file examples of various scenarios utilizing the DescribeSpotPriceHistory API call in Java[2].
For more details about DescribeSpotPriceHistory, kindly refer to the official documentation[3].
References
[1]. https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/ec2/AmazonEC2.html#describeSpotPriceHistory-com.amazonaws.services.ec2.model.DescribeSpotPriceHistoryRequest-
[2]. https://www.programcreek.com/java-api-examples/index.php?api=com.amazonaws.services.ec2.model.SpotPrice
[3]. https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeSpotPriceHistory.html

R - Connecting R and java using Rserve

I have build an application connecting R and java using the Rserve package.
In that, i am getting the error as "evaluation successful but object is too big to transport". i have tried increasing the send buffer size value in Rconnection class also. but that doesn't seem to work.
The object size which is being transported is 4 MB
here is the code from the R connection file
public void setSendBufferSize(long sbs) throws RserveException {
if (!connected || rt == null) {
throw new RserveException(this, "Not connected");
}
try {
RPacket rp = rt.request(RTalk.CMD_setBufferSize, (int) sbs);
System.out.println("rp is send buffer "+rp);
if (rp != null && rp.isOk()) {
System.out.println("in if " + rp);
return;
}
} catch (Exception e) {
e.printStackTrace();
LogOut.log.error("Exception caught" + e);
}
//throw new RserveException(this,"setSendBufferSize failed",rp);
}
The full java class is available here :Rconnection.java

Instead of RServe, you can use JRI, that is shipped with rJava package.
In my opinion JRI is better than RServe, because instead of creating a separate process it uses native calls to integrate Java and R.
With JRI you don't have to worry about ports, connections, watchdogs, etc... The calls to R are done using an operating system library (libjri).
The methods are pretty similar to RServe, and you can still use REXP objects.
Here is an example:
public void testMeanFunction() {
// just making sure we have the right version of everything
if (!Rengine.versionCheck()) {
System.err.println("** Version mismatch - Java files don't match library version.");
fail(String.format("Invalid versions. Rengine must have the same version of native library. Rengine version: %d. RNI library version: %d", Rengine.getVersion(), Rengine.rniGetVersion()));
}
// Enables debug traces
Rengine.DEBUG = 1;
System.out.println("Creating Rengine (with arguments)");
// 1) we pass the arguments from the command line
// 2) we won't use the main loop at first, we'll start it later
// (that's the "false" as second argument)
// 3) no callback class will be used
engine = REngine.engineForClass("org.rosuda.REngine.JRI.JRIEngine", new String[] { "--no-save" }, null, false);
System.out.println("Rengine created...");
engine.parseAndEval("rVector=c(1,2,3,4,5)");
REXP result = engine.parseAndEval("meanVal=mean(rVector)");
// generic vectors are RVector to accomodate names
assertThat(result.asDouble()).isEqualTo(3.0);
}
I have a demo project that exposes a REST API and calls R functions using this package.
Take a look at: https://github.com/jfcorugedo/RJavaServer

Java grph library: Exception on toools.os.OperatingSystem.getLocalOS()

I'm using grph library for a university project (www.i3s.unice.fr/~hogie/grph/)
but i have a problem only on Linux with that library, when i create a new Graph object, i receive the following exception:
Exception in thread "main" java.lang.ExceptionInInitializerError
at org.elendev.wesproject.graph.GraphFactory.main(GraphFactory.java:19)
Caused by: java.lang.NullPointerException
at toools.os.OperatingSystem.getLocalOS(OperatingSystem.java:47)
at grph.Grph.setCompilationDirectory(Grph.java:353)
at grph.Grph.<clinit>(Grph.java:246)
... 1 more
I tried to call directly getLocalOS function, with:
System.out.println(toools.os.OperatingSystem.getLocalOS());
and i receive the same exception. I cannot find information about that library, and the project launched on a macbook works perfectly.
The operating system i'm currently using is gentoo linux 32bit.
And the jdk version is: 1.7.0_65
Any idea of what could be the problem?

Not sure whether this can count as an answer, but it could at least help to solve the issue:
The exception comes from the toools.os.OperatingSystem.getLocalOS method. Although the .JAR file from the website that you mentioned has a whopping 39 megabytes, the source code of this class is not contained in it.
There seems to be no information available about this class at all. Neither Google nor Maven finds anything related to the toools package. One has to assume that it is an abandoned utility class that passed away a long time ago.
However, the method in question can be disassembled to the following code:
public static OperatingSystem getLocalOS()
{
if (localOS == null)
{
if (new RegularFile("/etc/passwd").exists())
{
if (new Directory("/proc").exists())
{
if (new RegularFile("/etc/fedora-release").exists()) {
localOS = new FedoraLinux();
} else if (ExternalProgram.commandIsAvailable("ubuntu-bug")) {
localOS = new UbuntuLinux();
} else {
localOS = new Linux();
}
}
else if (new Directory("/Applications").exists()) {
localOS = new MacOSX();
} else {
localOS = new Unix();
}
}
else if (System.getProperty("os.name").startsWith("Windows")) {
localOS = new Windows();
} else {
localOS = new OperatingSystem();
}
localOS.name = System.getProperty("os.name");
localOS.version = System.getProperty("os.version");
}
return localOS;
}
From this, you can possibly derive the conditions that must be met in order to properly detect your OS as a linux OS. Particularly, when there is a file named /etc/passwd, and a directory /proc, this should be sufficient to identify the OS as a Linux. You may want to give it a try...

Can Java launch the Windows UAC?

As the title says, I'm wondering if it is possible for a program written in Java (and only java) to relaunch himself (preferably a .jar) with administrator privileges, showing in the way the native Windows UAC (in order to make it more trustable for the user), i did my homework and found out that it is possible to accomplish this using bridges between c++ and java, but i would really like to do this as a pure java project.
P.S: In the remote case that this result to be impossible, can someone show me the "easy" way to do this using another language (i mean, I've found tutorials, but they are to complicated for something I think it should not be that complicated).
P.S2: In case it is possible to accomplish this, would it work, on other platforms (OS X, Linux)

It cannot be done in pure java.
Best bet would be to write this to a file:
#echo Set objShell = CreateObject("Shell.Application") > %temp%\sudo.tmp.vbs
#echo args = Right("%*", (Len("%*") - Len("%1"))) >> %temp%\sudo.tmp.vbs
#echo objShell.ShellExecute "%1", args, "", "runas" >> %temp%\sudo.tmp.vbs
#cscript %temp%\sudo.tmp.vbs
and save it as something.bat in Windows temp directory (as we have access to this).
You would then execute this from your application using Runtime or ProcessBuilder and exit your application (System.exit(0);).
You should add an immediate start up check to your application that checks if the program has elevation, if it has proceed if not re-run the batch and exit.
Here is an example I made (this must be run when compiled as a Jar or it wont work):
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import javax.swing.JOptionPane;
/**
*
* #author David
*/
public class UacTest {
public static String jarName = "UacTest.jar", batName = "elevate.bat";
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
if (checkForUac()) {//uac is on
JOptionPane.showMessageDialog(null, "I am not elevated");
//attempt elevation
new UacTest().elevate();
System.exit(0);
} else {//uac is not on
//if we get here we are elevated
JOptionPane.showMessageDialog(null, "I am elevated");
}
}
private static boolean checkForUac() {
File dummyFile = new File("c:/aaa.txt");
dummyFile.deleteOnExit();
try {
//attempt to craete file in c:/
try (FileWriter fw = new FileWriter(dummyFile, true)) {
}
} catch (IOException ex) {//we cannot UAC muts be on
//ex.printStackTrace();
return true;
}
return false;
}
private void elevate() {
//create batch file in temporary directory as we have access to it regardless of UAC on or off
File file = new File(System.getProperty("java.io.tmpdir") + "/" + batName);
file.deleteOnExit();
createBatchFile(file);
runBatchFile();
}
private String getJarLocation() {
return getClass().getProtectionDomain().getCodeSource().getLocation().getPath().substring(1);
}
private void runBatchFile() {
//JOptionPane.showMessageDialog(null, getJarLocation());
Runtime runtime = Runtime.getRuntime();
String[] cmd = new String[]{"cmd.exe", "/C",
System.getProperty("java.io.tmpdir") + "/" + batName + " java -jar " + getJarLocation()};
try {
Process proc = runtime.exec(cmd);
//proc.waitFor();
} catch (Exception ex) {
ex.printStackTrace();
}
}
private void createBatchFile(File file) {
try {
try (FileWriter fw = new FileWriter(file, true)) {
fw.write(
"#echo Set objShell = CreateObject(\"Shell.Application\") > %temp%\\sudo.tmp.vbs\r\n"
+ "#echo args = Right(\"%*\", (Len(\"%*\") - Len(\"%1\"))) >> %temp%\\sudo.tmp.vbs\r\n"
+ "#echo objShell.ShellExecute \"%1\", args, \"\", \"runas\" >> %temp%\\sudo.tmp.vbs\r\n"
+ "#cscript %temp%\\sudo.tmp.vbs\r\n"
+ "del /f %temp%\\sudo.tmp.vbs\r\n");
}
} catch (IOException ex) {
//ex.printStackTrace();
}
}
}

Use a batch file and the runas command.

I doubt "only Java". At best you would have to have a JNI wrapper around the MSFT module. Unless just invoking the exe using ProcessBuilder counts as "only Java" -- your code to bring up the user console would be only Java but not what it invokes. IOW, Win does not come with a Java API

To relaunch your application elevated, you have to call ShellExecute or ShellExecuteEx function from Windows API and use runas verb.
You can use these API in pure Java with JNA library.
To relaunch yourself, you would have to know the full path to java.exe or javaw.exe, the command-line parameters (class path, if any, and the path to your jar). Obviously you can get this information by using Windows API.
What do you mean by remote case?
You cannot start remote elevated process this way.
You can re-launch your application elevated from a network share. Yet it won't work with mapped drives: after elevation there's no access to user's mapped drives.
No, this can't work on other platforms. UAC is a Windows feature. It's similar to sudo in Linux in some ways, so for Linux you can use sudo $pathtojava/java.exe <yourparameters>. However this won't work nicely if your application is not started from a console. Window Managers usually have wrappers which prompt for password in a GUI dialog.

Just do this with Hackaprofaw (v29). Also it was released in 2002 and started development in 1997 soooooo ye. in 2021 its on version 29.10.7 but-
if raw ram = 0
disable "featureII" program = "JAVA(math = any)"
run on "Hackaprofaw (math = v29(x))
when "featureII" disabled
end