Accessing JVM from python

Question

>>> import boilerpipe
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Anaconda\lib\site-packages\boilerpipe\__init__.py", line 10, in <module>
    jpype.startJVM(jpype.getDefaultJVMPath(), "-Djava.class.path=%s" % os.pathsep.join(jars))
  File "C:\Anaconda\lib\site-packages\jpype\_core.py", line 50, in startJVM
    _jpype.startup(jvm, tuple(args), True)
RuntimeError: Unable to load DLL [C:\Program Files\Java\jre7\bin\client\jvm.dll], error = The specified module could not be found.
 at native\common\include\jp_platform_win32.h:58

Tried: Reinstalling jvm

>> import ctypes
>> import os
>> os.chdir(r"<path to Java bin client folder>")
>> ctypes.CDLL("jvm.dll")
Still unable to fix

Edit: Tried code below, still stuck:

from py4j.java_gateway import JavaGateway gateway = JavaGateway() It gives the same error as before.

Loading the JVM from a DLL is very hard even from C. I suggest you load the JVM using `java` from the command line or use Jython which runs in the JVM already. — Peter Lawrey, Aug 17 '15 at 08:20
@PeterLawrey Thanks for comment! I am unaware of `Jython`. Should I just install it and run my python script again? Or there is more to it? — Abhishek Bhatia, Aug 17 '15 at 08:40
Jython runs Python scripts inside the JVM. I assume there is more to it but this is designed and supported to work with the JVM it is running in. — Peter Lawrey, Aug 17 '15 at 08:53
https://stackoverflow.com/questions/3652554/calling-java-from-python — ρss, Aug 17 '15 at 09:48
@ρss I am very new using java in python. How can this solve my issue? I just want to simply use this package. — Abhishek Bhatia, Aug 17 '15 at 11:00
@ρss Tried this. `>>> from py4j.java_gateway import JavaGateway >>> gateway = JavaGateway() ` Still the same error. — Abhishek Bhatia, Aug 17 '15 at 13:03
@AbhishekBhatia Please update your question with the new tests that you have made, instead of mentioning them in a comment. — ρss, Aug 17 '15 at 14:59
Not an answer, but I would like to also recommend trying Jython. From Jython you can access everything in Java. What Jython is, is that you run Python *inside* Java and so direct access to everything inside Java. — Prof. Falken, Aug 20 '15 at 13:04
Also you don't say what the problem is with the last example. — Prof. Falken, Aug 20 '15 at 13:18
@Prof.Falken I don't want to install another python distribution. Is it possible to install `Jython` to already present python version. If that makes some sense. — Abhishek Bhatia, Aug 21 '15 at 07:08
@AbhishekBhatia, no, not exactly. You install it to already present *Java* installation. Or you just include the Jython **jar** file inside your Java project. Then nothing at all needs to be installed. http://www.jython.org/downloads.html — Prof. Falken, Aug 21 '15 at 11:58
@Prof.Falken Sorry I don't exactly understand. Please explain `Jython jar file inside your Java project`. Are you talking about the boilerpipe library here or my script which uses boilerpipe. — Abhishek Bhatia, Aug 21 '15 at 14:03
@AbhishekBhatia, I am saying that you if you had Jython, you could import any Java library. — Prof. Falken, Aug 21 '15 at 15:32
The problem with jython is that a lot of python stuff doesn't work with it (a lot of the more advanced modules out there use C extensions). I've had good initial success with [jpype](https://github.com/originell/jpype), though I haven't used it super extensively. — yshavit, Aug 22 '15 at 06:19

score 3 · Accepted Answer · answered Aug 22 '15 at 10:25

3

Check Please !

Give a true path ("C:\\Program Files\\Java\\jre7\\bin\client\\jvm.dll")
Check all 32 or 64 bit (my offer always use 32bit Anaconda,JRE7,Python etc.)
Install pywin32 (of course python2.7.9)
Give permission to jvm.dll(can run)
After all is ok, try: import ctypes ctypes.CDLL('C:\\Program Files\\Java\\jre7\\bin\\client\\jvm.dll')

***Maybe can't throw the hook of some java versions i used jre-7u55-windows-i586.exe

i hope helpful ! Best regards !

Works on wine(no bug):

answered Aug 22 '15 at 10:25

dsgdfg

1,492
11
18

3

Thanks! I get this error unforunately. `>>> ctypes.CDLL('C:\Program Files (x86)\Java\jre1.8.0_40\bin\client\jvm.dll') Traceback (most recent call last): File "", line 1, in File "C:\Anaconda\lib\ctypes\__init__.py", line 365, in __init__ self._handle = _dlopen(self._name, mode) WindowsError: [Error 126] The specified module could not be found` – Abhishek Bhatia Aug 22 '15 at 17:34
1

How does one give permission to the dll to "can run"? We are searching the web but the keywords are so generic we are not finding good answers. – Praxiteles Jul 19 '18 at 10:11
Depends on the operating system version. Some application extensions only require access (sometimes the right to access and/or user and/or user group and/or access class and/or service point etc.). – dsgdfg Jul 20 '18 at 09:04

knight · Answer 2 · 2015-08-27T10:46:59.113

3

Answering because I don't have enough rep for commenting; Try using raw strings instead of the normal ones allowing "\x" escapes. Try:

>>> ctypes.CDLL(r'C:\Program Files (x86)\Java\jre1.8.0_40\bin\client\jvm.dll')

Because the "\..." parts of the string could very well be escapes.

edited Aug 27 '15 at 10:46

answered Aug 25 '15 at 12:28

knight

435
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score 1 · Answer 3 · answered Dec 21 '18 at 00:21

The answers above are not sufficient, one also needs to install the Microsoft Visual C++ 2010 Redistributable Package (x86) as per Bjorns answer.

After installed the C++ redistributable:

Set JAVA_HOME environment variable to ("C:\Program Files\Java\jre7")
Use paths as mentioned above to start jvm:

path_to_jvm = "C:\Program Files\Java\jre7\bin\client\jvm.dll"

jpype.startJVM(path_to_jvm)

jpype.startJVM(jpype.getDefaultJVMPath())

score 1 · Answer 4 · answered Sep 05 '19 at 22:47

If you are trying to access JVM on Windows operation system, make sure you have the right version of JVM (32-bit or 64-bit) installed. In my case python was 64-bit and once I installed Java 64-bit, it worked without needing to specify the path or any other extra requirements.

Accessing JVM from python

4 Answers4

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