Qt Creator - JNI Error: libjvm.so: cannot open shared object file: No such file or directory

Ibrahim

Hi; I'm trying JNI in Qt Creator in Ubuntu. But I get this error message:
error while loading shared libraries: libjvm.so: cannot open shared object file: No such file or directory

My .pro file:

QT += core
QT -= gui

CONFIG += c++11
CONFIG += -ljvm

TARGET = JNIExample
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

INCLUDEPATH += /usr/lib/jvm/java-8-oracle/include
INCLUDEPATH += /usr/lib/jvm/java-8-oracle/include/linux
LIBS += -L/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server/libjvm.so

SOURCES += main.cpp

DISTFILES += \
    myclasses/com/xxx/Code.java

My main.cpp file:

#include <QCoreApplication>
#include <jni.h>
#include <iostream>
using namespace std;

int main(int argc, char* argv[])
{
  QCoreApplication a(argc, argv);

  JavaVM* jvm;
  JNIEnv* env;
  JavaVMInitArgs jvm_args;
  JavaVMOption options[1];

  options[0].optionString = "-Djava.class.path=myclasses/com/xxx";
  jvm_args.version = JNI_VERSION_1_8;
  jvm_args.options = options;
  jvm_args.nOptions = 1;
  jvm_args.ignoreUnrecognized = JNI_TRUE;

  jint res = JNI_CreateJavaVM(&jvm, (void**)&env, &jvm_args);
  if (res < 0)
  {
    cout << "Cannot create JVM!\n";
    exit(1);
  }

  jclass class_ = env->FindClass("Code");
  if (class_ == 0)
  {
    cout << "Code class not found!\n";
    exit(1);
  }

  jmethodID method_id = env->GetMethodID(class_, "getMessage", "()V");
  if (method_id == 0)
  {
    cout << "getMessage() method not found!\n";
    exit(1);
  }

  env->CallVoidMethod(class_, method_id);

  return a.exec();
}

How can I run JNI code? Thanks.

p3c0

@Ibrahim

LIBS += -L/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server/libjvm.so

Wrong usage. It should be something like:

LIBS += -L/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server/ -ljvm

And remove CONFIG += -ljvm.
CONFIG has different purpose.

The best way to avoid these errors is to add library from QtCreator itself.
QtCreator > Project's .pro file > Add Library > External Library

Ibrahim

@p3c0 said in Qt Creator - JNI Error: libjvm.so: cannot open shared object file: No such file or directory:

@Ibrahim

LIBS += -L/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server/libjvm.so

Wrong usage. It should be something like:
LIBS += -L/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server/ -ljvm
And remove CONFIG += -ljvm.
CONFIG has different purpose.

The best way to avoid these errors is to add library from QtCreator itself.
QtCreator > Project's .pro file > Add Library > External Library

Thanks, it is works! But I get this error: Code class not found!

Code.java:

package com.xxx;

public class Code
{
  public void getMessage()
  {
    System.out.println("Hello from Java!");
  }
}

Directory:

I tried -Djava.class.path=myclasses/com/xxx and env->FindClass("Code"); like my first message. Also I tried -Djava.class.path=myclasses and env->FindClass("com/xxx/Code");. But both not working. What is reason of Code class not found! message?

p3c0

@Ibrahim Not quite sure but I guess the Java class will need a main method?
Try adding one.

Unsolved Qt Creator - JNI Error: libjvm.so: cannot open shared object file: No such file or directory