I am trying to run a simple Java program using C++ and wrote the following code-
1 #include <jni.h>
2 #include <stdio.h>
3
4 JNIEnv * create_vm() {
5 JavaVM *jvm;
6 JNIEnv *env;
7 JavaVMInitArgs vm_args;
8
9 JavaVMOption options[1];
10
11 options[0].optionString = "-Djava.class.path=~/openbr/java/JavainC";
12 vm_args.version = JNI_VERSION_1_6;
13 vm_args.nOptions = 1;
14 vm_args.options = options;
15 vm_args.ignoreUnrecognized = JNI_FALSE;
16
17 int res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);
18 return env;
19 }
20
21 void run_java(JNIEnv* env) {
22 jclass cls;
23 jmethodID mid;
24 jint square;
25
26 cls = env->FindClass("javaTest");
27 mid = env->GetStaticMethodID(cls, "square", "(I)I");
28 square = env->CallStaticIntMethod(cls, mid, 5);
29 printf("Result of square: %d\n", square);
30 }
31
32 int main() {
33 JNIEnv* env = create_vm();
34 run_java(env);
35 printf("running some code");
36 //jvm->DestroyJavaVM();
37 return 0;
38 }
My Java Code looks like-
1 public class javaTest {
2 public static int square(int n) {
3 return n*n;
4 }
5 }
6
My code compiled fine but when I tried to run it I got this error message-
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007fc3038f984f, pid=12689, tid=140475565049664
#
# JRE version: 7.0_21-b02
# Java VM: OpenJDK 64-Bit Server VM (23.7-b01 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# V [libjvm.so+0x53284f] jni_CallStaticIntMethodV+0x4f
#
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit - c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /home/jcheney/openbr/java/JavainC/hs_err_pid12689.log
#
# If you would like to submit a bug report, please include
# instructions on how to reproduce the bug and visit:
# https://bugs.launchpad.net/ubuntu/+source/openjdk-7/
#
Aborted
The error printout it gave me said-
--------------- T H R E A D ---------------
Current thread (0x00000000011be800): JavaThread "main" [_thread_in_vm, id=12689, stack
(0x00007fff54814000,0x00007fff54914000)]
siginfo:si_signo=SIGSEGV: si_errno=0, si_code=1 (SEGV_MAPERR), si_addr=0x0000000000000000
Registers:
RAX=0x00007fc303c4a138, RBX=0x00000000011be800, RCX=0x00007fff549127c0, RDX=0x00000000011bf318
RSP=0x00007fff549126e0, RBP=0x00007fff54912790, RSI=0x00000000011be800, RDI=0x00000000011be800
R8 =0x00007fc3038f9800, R9 =0x746f7073746f682f, R10=0x6168732f6372732f, R11=0x0000000000000246
R12=0x00000000011be9d8, R13=0x0000000000000000, R14=0x00007fff549127c0, R15=0x0000000000000000
RIP=0x00007fc3038f984f, EFLAGS=0x0000000000010287, CSGSFS=0x0000000000000033,
ERR=0x0000000000000004
TRAPNO=0x000000000000000e
Top of Stack: (sp=0x00007fff549126e0)
0x00007fff549126e0: 00007fff549126c8 0000000800000002
0x00007fff549126f0: 00007fff54912701 0000000000000000
0x00007fff54912700: 00007fff54912730 00007fc3038125ac
0x00007fff54912710: 00000000011be800 00000000011be800
0x00007fff54912720: 00000000011be800 00000000011bf310
0x00007fff54912730: 00007fff0000063d 00007fc303c4a138
0x00007fff54912740: 0000000000000000 0000000000400901
0x00007fff54912750: 00000000011be800 0000000000000000
0x00007fff54912760: 00000000011be800 0000000000400906
0x00007fff54912770: 0000000000000000 00000000004004d0
0x00007fff54912780: 00007fff549129d0 0000000000000000
0x00007fff54912790: 00007fff54912890 00000000004007cd
0x00007fff549127a0: 0000000000000000 0000000000000000
0x00007fff549127b0: 0000000000000000 00000000011be9d8
0x00007fff549127c0: 0000003000000018 00007fff549128a0
0x00007fff549127d0: 00007fff549127e0 0000000000400901
0x00007fff549127e0: 0000000000000000 0000000000000000
0x00007fff549127f0: 00007fff54912860 0000000000000005
0x00007fff54912800: 00007fc303c3ae8f 746f7073746f682f
0x00007fff54912810: 00007fff000000a8 00007fc303c68e68
0x00007fff54912820: 00000000011be800 00007fff549128c0
0x00007fff54912830: 00000000011be800 00007fc303903233
0x00007fff54912840: 0000000000000000 00000000004004d0
0x00007fff54912850: 00007fff549129d0 0000000000000000
0x00007fff54912860: 00007fff54912890 0000000000400712
0x00007fff54912870: 0000000000400901 0000000000400906
0x00007fff54912880: 0000000000000000 00000000011be9d8
0x00007fff54912890: 00007fff549128d0 000000000040065b
0x00007fff549128a0: 00000000004008d0 00000000011be9d8
0x00007fff549128b0: 00007fff54912930 0000000000000000
0x00007fff549128c0: 0000000000000000 00000000004007e0
0x00007fff549128d0: 00007fff549128f0 0000000000400691
Any ideas on what is going on?
Thanks
My guess -- and it's only a guess at this point -- is that one of the methods FindClass or GetStaticMethodId is not succeeding for some reason, and since you're not checking for errors, your program eventually crashes trying to call a method through a bad method pointer. Minimally, check the return values of both of these methods against NULL, and fail if that's what they return.
At @TimBender's urging, I looked at your code again, and I agree -- it's probably FindClass. You definitely can't include a ~ in your classpath -- only the shell knows how to interpret that, and that parameter won't go through a shell before the JVM sees it. Use a full, absolute path to the location of the class -- the root of the package hierarchy, actually.