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我已经用JNI写了一个Hello,world程序。 Java使用字符串调用c程序,c程序打印该字符串。这里是java程序JNI内存泄漏
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class JNISample {
public native void leakMem(String str);
static {
System.loadLibrary("sample");
}
public static void main(String args[]) throws IOException {
JNISample sample = new JNISample();
sample.leakMem("Hello world!");
}
}
相应的C程序
#include <stdlib.h>
#include <jni.h>
#include "JNISample.h"
JNIEXPORT void JNICALL Java_JNISample_leakMem(JNIEnv *env, jobject jobj, jstring givenStr) {
const char *javaStr = env->GetStringUTFChars (givenStr, 0);
printf("Received String: %s\n", javaStr);
env->ReleaseStringUTFChars (givenStr, javaStr);
}
当我执行此程序的valgrind,用下面的命令
valgrind --trace-children=yes --show-reachable=yes --leak-check=full java -Djava.library.path=. JNISample 10 2> log
我已经在日志中观察到的肯定失去了字节,这里是valgrind的记忆总结
LEAK SUMMARY:
==5385== definitely lost: 5,246 bytes in 36 blocks
==5385== indirectly lost: 5,072 bytes in 23 blocks
==5385== possibly lost: 154,317 bytes in 131 blocks
==5385== still reachable: 6,164,933 bytes in 831 blocks
==5385== suppressed: 0 bytes in 0 blocks
为什么在没有任何内存分配的情况下,这样的小程序肯定会丢失字节? JNI用法或JNI泄漏内存有问题吗?我在Ubuntu 11.10 64位机器上使用了JDK6。