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POMemory leak when calling java code from C using JNI
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copied!<p>I have a C program that stores some object in java store using JNI. (Before someone ask, using java store is a requirment here and I have to write a client in C which would be able to add and retrieve objects from this store).</p> <p>I made the program and tried to add 100000 object of size 1KB. But after adding only 50000 objects I am getting 'out of memory' messages (please note that I am printing these 'out of memory' messages whenever I am unable to allocate a new string or byte array using NewStringUTF and NewByteArray functions). At that time my application is using only 80MB of memory. I dont why these methods are returning NULL. Is there something I am missing.</p> <p>Furthermore, the memory keeps on increasing even though I am releasing byte array and string created for java.</p> <p>Here is the source code.</p> <pre><code> void create_jvm(void) { JavaVMInitArgs vm_args; JavaVMOption vm_options; vm_options.optionString = "-Djava.class.path=c:\\Store"; vm_args.version = JNI_VERSION_1_4; vm_args.nOptions = 1; vm_args.options = &vm_options; vm_args.ignoreUnrecognized = 0; JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args); if(env != null) { j_store = (*env)->FindClass(env, "com/store"); if(j_store == null) { printf("unable to find class. class name: JStore"); } } } void add(char* key, char* value, int length) { jstring j_key = (*env)->NewStringUTF(env, key); jbyteArray j_value = (*env)->NewByteArray(env, length); (*env)->SetByteArrayRegion(env, j_value, 0, length, (jbyte *)value); ret = (*env)->CallStaticBooleanMethod(env, j_store, method_id, j_key, j_value); if(j_value != null) { (*env)->ReleaseByteArrayElements(env, j_value, (jbyte *)value, 0); } if(j_key != null) { (*env)->ReleaseStringUTFChars(env, j_key, key); } } </code></pre> <p>The java side recieves the data in byte[] and stores it in a hashtable. The issue is that everytime the code runs the memory only adds up and is never released. I tried to add 1 MB object and debugged it.</p> <p>The process memory increases by 1MB when I call NewByteArray. But when CallStaticBooleanMethod is called the process memory increase by 4MB. And the call to ReleaseByteArrayElements do not release any memory at all.</p> <p>If I add another 1MB object after this, then process memory remains same when I call NewByteArray and it increase by 1MB when I call CallStaticBooleanMethod but remains the same when I try to release the byte array.</p>

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