I want to execute a Python function which is located in one of my python projects from java by using jython. https://smartbear.com/blog/test-and-monitor/embedding-jython-in-java-applications/ is giving the sample code for the purpose. But in my scenario I got the following exception.
Exception in thread "main" Traceback (most recent call last): File
"", line 1, in ImportError: No module named
JythonTestModule
My scenario is as follows.
I have created a python module inside my python project(pythonDev) by using PyCharm(JythonTestModule.py) which contains the following function.
def square(value):
return value*value
Then I created a sample java class in my java project(javaDev) and called the python module.
public static void main(String[] args) throws PyException{
PythonInterpreter pi = new PythonInterpreter();
pi.exec("from JythonTestModule import square");
pi.set("integer", new PyInteger(42));
pi.exec("result = square(integer)");
pi.exec("print(result)");
PyInteger result = (PyInteger)pi.get("result");
System.out.println("result: "+ result.asInt());
PyFunction pf = (PyFunction)pi.get("square");
System.out.println(pf.__call__(new PyInteger(5)));
}
After running this java method the aforementioned exception is generated by the java program. I want to know what is the problem with this menioned code segments.
As from the suggestions from the above comments section of this question, I have developed the solution to my question. Following code segment will demonstrate that. In this solution I have set the python.path as the directory path to my module file.
public static void main(String[] args) throws PyException{
Properties properties = new Properties();
properties.setProperty("python.path", "/path/to/the/module/directory");
PythonInterpreter.initialize(System.getProperties(), properties, new String[]{""});
PythonInterpreter pi = new PythonInterpreter();
pi.exec("from JythonTestModule import square");
pi.set("integer", new PyInteger(42));
pi.exec("result = square(integer)");
pi.exec("print(result)");
PyInteger result = (PyInteger)pi.get("result");
System.out.println("result: "+ result.asInt());
PyFunction pf = (PyFunction)pi.get("square");
System.out.println(pf.__call__(new PyInteger(5)));
}
If you want to use multiple modules from the Jython, add the python.path as the parent directory path of all the modules in order to detect all the modules.
I am attempting to get a log output from the displayLogs() command and I have trying to do this within the WLST Interpreter. I get the following error which is "NameError: displayLogs" I am able to perform other commands such as domainRuntime() and a number of others, but this one seems to be outside the realm. Do I need to run it with some sort of classes in the classpath when running it? Any help would be appreciated.
The source code that I am using below:
package wlst;
import weblogic.management.scripting.utils.WLSTInterpreter;
import org.python.util.InteractiveInterpreter;
import org.python.core.PyObject;
public class EmbeddedWLST
{
static InteractiveInterpreter interpreter = null;
EmbeddedWLST() {
interpreter = new WLSTInterpreter();
}
private static void connect() {
StringBuffer buffer = new StringBuffer();
buffer.append("connect('USERNAME','PASSWORD','t3://HOSTANAME:PORT')");
interpreter.exec(buffer.toString());
}
public static void main(String[] args) {
new EmbeddedWLST();
connect();
PyObject cmo = interpreter.get("cmo");
String command = getLogs();
System.out.println("Executing Get Logs");
interpreter.exec(command);
System.out.println("Getting Output Object");
PyObject output = interpreter.get("output");
System.out.println(output.getClass());
System.out.println(output);
}
private static String getLogs() {
StringBuffer buf = new StringBuffer();
buf.append( "output = displayLogs(returnData=1)\n" );
return buf.toString();
}
}
UPDATE
Everything you are looking for lives in:
<install dir>/oracle_common/common/wlst
A simple grep -R displayLogs * returned the python module you need:
<install dir>/oracle_common/common/wlst/oracle-logging.py
You will need to include the jars that script needs on your classpath, specifically the logging jar ojdl.jar found under <install dir>/oracle_common/modules/oracle.odl
The above information was found by comparing the scripts below (I am using 10.3.6):
This script <install dir>/wlserver_10.3/common/bin/wlst.sh fails with:
wls:/offline> listLogs()
Traceback (innermost last):
File "<console>", line 1, in ?
NameError: listLogs
This script <install dir>/oracle_common/common/bin/wlst.sh succeeds (and has many more options than the script above) :
wls:/offline> listLogs()
Not connected to a Weblogic server. Connect to a Weblogic server first.
Make sure you have all the same jars and properties set as the second script does.
Here is what my code looks like:
public class ExcelManip {
public static void main(String args[])
throws ExcelException, FileNotFoundException {
Application application = new Application();
File xslFile =
new File("C:\\Users\\Nathan.Shnipes\\Documents\\Workbook.xlsx");
Workbook workbook = application.openWorkbook(xslFile, true);
Worksheet worksheet = workbook.getWorksheet(1);
Range range = worksheet.getRange("A1:AD1");
Variant[][] results = range.getValues();
Cell cell = worksheet.getCell("A1");
System.out.println(cell.getString());
System.out.println(results[0][0].getValue());
System.out.println(
"C:\\Users\\Nathan.Shnipes\\Documents\\Workbook.xlsx");
Range range2 = worksheet.getRange("o1:o500");
Variant[][] dates = range2.getValues();
System.out.println(dates[0][0].getValue());
}
}
or as an image:
It's been throwing an error consistently on line 35. I deleted everything past line 35 as it worked up to that point, but it didn't help. I really have no idea whats wrong. I have tried copying the body of the program and placing it into a new class, but for whatever reason that has been throwing a no main error, even though it had the line public static void main(String[] args) throws ***
You have a red exclamaition mark on your project. Eclipse is likly to not build your project if build path problems (e.g.) aren't resolved. So go to the Problems tab and try to resolve your errors there. If that is finished Eclipse will build your project and gives more helpful errors
Edit
and that is why you are running the old version (no new build replaced your old one), in which there is actually a line 35.
I'd like to write a Java app which can create executable jars at runtime. The "hello world" of what I want to do is write a Java app X that when run, generates an executable jar Y that when run, prints hello world (or perhaps another string not known until after Y is run).
How can I accomplish this?
The other answers require starting a new process, this is a method that doesn't. Here are 3 class definitions which produce the hello world scenario described in the question.
When you run XMain.main, it generates /tmp/y.jar. Then, when you run this at the command line:
java -jar /tmp/y.jar cool
It prints:
Hello darling Y!
cool
example/YMain.java
package example;
import java.io.IOException;
import java.io.InputStream;
public class YMain {
public static void main(String[] args) throws IOException {
// Fetch and print message from X
InputStream fromx = YMain.class.getClassLoader().getResourceAsStream("fromx.txt");
System.out.println(new String(Util.toByteArray(fromx)));
// Print first command line argument
System.out.println(args[0]);
}
}
example/XMain.java
package example;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;
import java.util.jar.Manifest;
public class XMain {
public static void main(String[] args) throws IOException {
Manifest manifest = new Manifest();
manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
manifest.getMainAttributes().put(Attributes.Name.MAIN_CLASS, YMain.class.getName());
JarOutputStream jarOutputStream = new JarOutputStream(new FileOutputStream("/tmp/y.jar"), manifest);
// Add the main class
addClass(YMain.class, jarOutputStream);
// Add the Util class; Y uses it to read our secret message
addClass(Util.class, jarOutputStream);
// Add a secret message
jarOutputStream.putNextEntry(new JarEntry("fromx.txt"));
jarOutputStream.write("Hello darling Y!".getBytes());
jarOutputStream.closeEntry();
jarOutputStream.close();
}
private static void addClass(Class c, JarOutputStream jarOutputStream) throws IOException
{
String path = c.getName().replace('.', '/') + ".class";
jarOutputStream.putNextEntry(new JarEntry(path));
jarOutputStream.write(Util.toByteArray(c.getClassLoader().getResourceAsStream(path)));
jarOutputStream.closeEntry();
}
}
example/Util.java
package example;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
public class Util {
public static byte[] toByteArray(InputStream in) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buf = new byte[0x1000];
while (true) {
int r = in.read(buf);
if (r == -1) {
break;
}
out.write(buf, 0, r);
}
return out.toByteArray();
}
}
Do you have to write it in plain old Java? I'd use Gradle (a Groovy based build tool). You can have a custom task to write out the source files for Y (Groovy makes it really easy to write out templated files). Gradle makes it easy to generate an executable jar.
If you really want to roll your own from scratch, you'd need to use ZipOutStream to zip up the compiled files after calling javac via the Process API to compile the source.
Maybe a bit more info about why you want to do this would help get better answers
cheers
Lee
To elaborate on Lee's reply, you need to compile the source first. You can use Process or you can use the code from tools.jar directly as explained here. Then write out a MANIFEST.MF file and put it all together using ZipOutputStream as mentioned.
Step 1: figure out how to do it manually using the command line.
Step 2: automate this by calling the program from within Java.
http://devdaily.com/java/edu/pj/pj010016/
For step 1 I would suggest using ant - IDEs are not always automatable. So, either write out all the files from Java, or have some of the ant configurations included as resources n the project.
I used
Runtime.getRuntime().exec("_____")
but it throws a IOException as below:
java.io.IOException: CreateProcess: c:/ error=5
at java.lang.Win32Process.create(Native Method)
at java.lang.Win32Process.<init>(Win32Process.java:63)
at java.lang.Runtime.execInternal(Native Method
I don't know whether I have the problem with specifying the path or something else. Can anyone please help me with the code.
You're trying to execute "C:/". You'll want to execute something like:
"javaw.exe d:\\somejavaprogram\\program.jar"
Notice the path separators.
I'm assuming this is for an ad-hoc project, rather than something large. However, for best practice running external programs from code:
Don't hardcode the executable location, unless you're certain it will never change
Look up directories like %windir% using System.getenv
Don't assume programs like javaw.exe are in the search path: check them first, or allow the user to specify a location
Make sure you're taking spaces into account: "cmd /c start " + myProg will not work if myProg is "my program.jar".
You can either launch another JVM (as described in detail in other answers).
But that is not a solution i would prefer.
Reasons are:
calling a native program from java is "dirty" (and sometimes crashes your own VM)
you need to know the path to the external JVM (modern JVMs don't set JAVA_HOME anymore)
you have no control on the other program
Main reason to do it anyway is, that the other application has no control over your part of the program either. And more importantly there's no trouble with unresponsive system threads like the AWT-Thread if the other application doesn't know its threading 101.
But! You can achieve more control and similar behaviour by using an elementary plugin technique. I.e. just call "a known interface method" the other application has to implement. (in this case the "main" method).
Only it's not quite as easy as it sounds to pull this off.
you have to dynamically include required jars at runtime (or include them in the classpath for your application)
you have to put the plugin in a sandbox that prevents compromising critical classes to the other application
And this calls for a customized classloader. But be warned - there are some well hidden pitfalls in implementing that. On the other hand it's a great exercise.
So, take your pick: either quick and dirty or hard but rewarding.
java.io.IOException: CreateProcess: c:/ error=5
at java.lang.Win32Process.create(Native Method)
at java.lang.Win32Process.<init>(Win32Process.java:63)
at java.lang.Runtime.execInternal(Native Method)
If I recall correctly, error code 5 means access denied. This could be because your path is incorrect (trying to execute "c:/") or you are bumping against your OS security (in which case, look at the permissions).
If you are having trouble locating the Java executable, you can usually find it using system properties:
public class LaunchJre {
private static boolean isWindows() {
String os = System.getProperty("os.name");
if (os == null) {
throw new IllegalStateException("os.name");
}
os = os.toLowerCase();
return os.startsWith("windows");
}
public static File getJreExecutable() throws FileNotFoundException {
String jreDirectory = System.getProperty("java.home");
if (jreDirectory == null) {
throw new IllegalStateException("java.home");
}
File exe;
if (isWindows()) {
exe = new File(jreDirectory, "bin/java.exe");
} else {
exe = new File(jreDirectory, "bin/java");
}
if (!exe.isFile()) {
throw new FileNotFoundException(exe.toString());
}
return exe;
}
public static int launch(List<String> cmdarray) throws IOException,
InterruptedException {
byte[] buffer = new byte[1024];
ProcessBuilder processBuilder = new ProcessBuilder(cmdarray);
processBuilder.redirectErrorStream(true);
Process process = processBuilder.start();
InputStream in = process.getInputStream();
while (true) {
int r = in.read(buffer);
if (r <= 0) {
break;
}
System.out.write(buffer, 0, r);
}
return process.waitFor();
}
public static void main(String[] args) {
try {
Runtime.getRuntime().exec("c:/");
List<String> cmdarray = new ArrayList<String>();
cmdarray.add(getJreExecutable().toString());
cmdarray.add("-version");
int retValue = launch(cmdarray);
if (retValue != 0) {
System.err.println("Error code " + retValue);
}
System.out.println("OK");
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
(Tested Windows XP, Sun JRE 1.6; Ubuntu 8.04, OpenJDK JRE 1.6)
This is the equivalent of running:
java -version
You may also want to look at the "java.library.path" system property (and "path.separator") when trying to locate the executable.
How about just calling the main from your java program?
Test.main(null);
This worked fine for me
Is there any reason you can't just call it directly in your Java code?
If there is a reason I've not tried it for executing a Java Program but you could try Jakarta Commons Exec works well for executing most programs.
I had to do this recently.
Here is how I did it, picking up only the relevant parts:
private static final String[] straJavaArgs =
{
"?i/j2re/bin/java",
"-ms64m",
"-mx64m",
"-Djava.ext.dirs=?i/lib;?i/jar/lib;?i/jar"
};
// ...
// AppDesc appToRun;
List<String> params = new ArrayList<String>();
// Java exe and parameters
params.addAll(ExpandStrings(straJavaArgs));
// Common VM arguments
params.addAll(Arrays.asList(AppDesc.GetCommonVMArgs()));
// Specific VM arguments
params.addAll(ExpandStrings(appToRun.GetVMArgs()));
// The program to run
params.add(appToRun.GetClass());
// Its arguments
params.addAll(ExpandStrings(appToRun.GetProgramArgs()));
// The common arguments
params.addAll(ExpandStrings(AppDesc.GetCommonProgramArgs()));
ProcessBuilder processBuilder = new ProcessBuilder(params);
process = processBuilder.start();
return CaptureProcessOutput(); // Uses a StreamGobbler class
protected ArrayList<String> ExpandStrings(String[] stra)
{
ArrayList<String> alResult = new ArrayList<String>();
for (int i = 0; i < stra.length; i++)
{
// Super flexible, eh? Ad hoc for the current task, at least...
alResult.add(stra[i]
.replaceAll("\\?i", strInstallDir)
.replaceAll("\\?c", strConfigDir)
);
}
return alResult;
}
public enum AppDesc
{
// Enumerate the applications to run, with their parameters
}
Incomplete, if you need more details, just ask.
public class Test {
public static void main(String[] args) throws Exception {
Process p = Runtime.getRuntime().exec("\"c:/program files/windows/notepad.exe\"");
p.waitFor();
}
}
The above works quite well, instead of passing \"c:/program files/windows/notepad.exe\" as the arguments for the executable, use the path to your program, I'm not sure if this solution is JVM version dependent, or if it can use relative paths.
You must pass the path of your executable at the exec method. Are you really trying to execute the "-" process?
Also, have a look at this for some useful tips.
Put ant lib in you classpath ( project lib ) and run this code :
import org.apache.tools.ant.taskdefs.Execute;
Execute exe = new Execute();
exe.setCommandline(new String[]{"java", "-version"});
exe.execute();
I can't remember the exact code that I used to get this to work, but you have to pass "java.exe" (or the equivalent) as the executable, and then the class or jar to run as the parameter, with the correct working directory. So it's not as simple as just calling one method.
I had a similiar problem. I needed to run a section of Java code in a seperate VM as it invoked native code via JNI that occasionally blew up taking out the entire VM.
I cheated a little though. I initially used Runtime to invoke a simple batch command file and put the work-in-progress java command in there. This enabled me to tweak it as needed and to run the command in a DOS prompt for easy testing. Once it was finished I simply copied the result into the Runtime invocation.
First you compile the prog-A code and convert to jar file(ie:In NetBeans Shift-F11)and the path is of netbeans(NetBeansProjects/prog-A/dist/prog-A.jar)
public class ProgA {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
System.out.println("Helllo print thr ProgA");
}
}
}
Second open the new project in prog-B and add the libraries, and select the jar and give to the prog-A.jar file and write the two line in your program
public class ProgB {
public static void main(String[] args) {
ProgA progA = new ProgA();
String arg[] = null;
progA.main(arg);
}
}
I agree with Ushsa Varghese, if you just want to run your jar file instead of compiling the .java file that is in the same directory you are executing your application from try the code below. This is the same as executing your java application from the command line so you have to invoke the jvm in order to run your application. Also make sure you have the complete path to your jar file the example below assumes that the jar file is in the same directory as the application that is executing the code below. keep in mind this is system dependent code.
try {
Runtime runTime = Runtime.getRuntime();
Process process = runTime.exec("java -jar deleteDriveC.jar");
} catch (IOException ex) {
//jar file doesnt exist
//Logger.getLogger(this.class.getName()).log(Level.SEVERE, null, ex);
}
The answer is simple all you have to do is put the code -
$ process p = Runtime.getRuntime().exec("javac factorial.java"); in the try catch block
The code would look like this -
try
{
process p = Runtime.getRuntime().exec("javac factorial.java");
}
catch(IOException e)
{
e.printStackTrace();
}
Hey I think this should work. Atleast for me it did work