Error Calling a Java Method From Native C++ Using JNI (ACCESS_VIOLATION error)

Question

I got a problem : I try to call a java method that's supposed to print something in the console. It is called from a C++ native dll using JNI. The problem is that it won't work and I get that error :

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x6c5f5253, pid=4472, tid=4956
#
# JRE version: 6.0_29-b11
# Java VM: Java HotSpot(TM) Client VM (20.4-b02 mixed mode, sharing windows-x86 )
# Problematic frame:
# C  0x6c5f5253
#
# An error report file with more information is saved as:
# C:\location\MyApp\hs_err_pid4472.log
#
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
#

Here is the C++ code I use to call a simple java method that will print a row in console :

jclass jTablObjClass = env->FindClass("MainFrame/Jni/TablesObjects");           // get jclass   
jmethodID printMethId = env->GetMethodID(jTablObjClass, "print", "()V");        // get jmethod
env->CallVoidMethod(jTablObjClass, printMethId);                                // call jmethod

Please, help ! ^^

Add return value checks to find out precise place of failure. Check all return values if they are not null. — kan
– kan, Commented Nov 21, 2011 at 10:08
In fact, the source of the crash is the call of the void java method env->CallVoidMethod(jTablObjClass, printMethId); But there's actually no reason for it to crash so ... — Jsncrdnl
– Jsncrdnl, Commented Nov 21, 2011 at 10:16
How could I check that plz ? Is there a function I should use ? — Jsncrdnl
– Jsncrdnl, Commented Nov 21, 2011 at 10:24
if(jTablObjClass == NULL) {report an error and do something} — kan
– kan, Commented Nov 21, 2011 at 10:25

kan · Accepted Answer · 2011-11-21 10:24:15Z

2

Oh, just realized. You are calling CallVoidMethod but the first argument is a class. If the method is a static, you should use GetStaticMethodID and CallStaticVoidMethod, if the method is not static, you should give an object instance, not a class.

answered Nov 21, 2011 at 10:24

kan

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Jsncrdnl Over a year ago

Thank you very much ! You are great! I tried to set my java method "static" and in my native c++ code, I call the GetStaticMethodID and then the CallStaticVoidMethod and it actually did work out ! ^^ So thank you so much !

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