Падонки думают, как сделать чтобы объект не двигался по хипу:
http://www.java‑gaming.org/index.php/topic,21036.
pjt33@agape:/tmp/jni/$ cat testPin.c
#include «jni.h»
JNIEXPORT jclass JNICALL Java_TestPin_pinStringClass(JNIEnv * env, jclass clazz)
{
static jclass stringClass = NULL;
if (stringClass == NULL) {
jclass localRefCls =
(*env)->FindClass(env, "java/lang/String");
if (localRefCls == NULL) {
return NULL; /* exception thrown */
}
/* Create a global reference */
stringClass = (*env)->NewGlobalRef(env, localRefCls);
/* The local reference is no longer useful */
(*env)->DeleteLocalRef(env, localRefCls);
/* Is the global reference created successfully? */
if (stringClass == NULL) {
return NULL; /* out of memory exception thrown */
}
}
pjt33@agape:/tmp/jni/$ gcc -o libtestPin.so -shared -I/usr/lib/jvm/jdk/include -I/usr/lib/jvm/jdk/include/linux testPin.c -static
pjt33@agape:/tmp/jni/$ cat TestPin.java
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import sun.misc.Unsafe;
public class TestPin
{
public static native Class pinStringClass();
static
{
System.loadLibrary("testPin");
}
public static void main(String[] args) throws Exception
{
Class foo = pinStringClass();
System.out.println(getObjectAddress(foo));
// Churn to force some GC.
ArrayList list = new ArrayList();
for (int i = 0; i 664K(5056K), 0.0059970 secs]
[GC 1560K->1456K(5056K), 0.0055870 secs]
[GC 2352K->2351K(5056K), 0.0064100 secs]
[GC 3247K->3247K(5056K), 0.0052960 secs]
[GC 4143K->4141K(5056K), 0.0060390 secs]
[GC 5037K->5036K(5960K), 0.0048390 secs]
[Full GC 5036K->4462K(5960K), 0.0485570 secs]
[GC 5358K->5356K(8400K), 0.0053860 secs]
[GC 6024K->6015K(8400K), 0.0046480 secs]
[GC 6911K->6911K(8400K), 0.0040350 secs]
[GC 7807K->7805K(8784K), 0.0063760 secs]
[Full GC 7805K->7288K(8784K), 0.0641510 secs]
[GC 8184K->8182K(13108K), 0.0054620 secs]
[GC 10241K->10240K(13108K), 0.0070920 secs]
[GC 11136K->11135K(13108K), 0.0062270 secs]
[GC 12031K->12029K(13108K), 0.0061340 secs]
[GC 12925K->12924K(13876K), 0.0064870 secs]
[Full GC 12924K->12149K(13876K), 0.0930100 secs]
[GC 15366K->15365K(21852K), 0.0107320 secs]
[GC 16837K->16836K(21852K), 0.0101650 secs]
[GC 18308K->18306K(21852K), 0.0291330 secs]
[GC 19778K->19778K(21852K), 0.0105530 secs]
[GC 20703K->20689K(22236K), 0.0078490 secs]
[Full GC 20689K->19304K(22236K), 0.1392640 secs]
[GC 24098K->24097K(34608K), 0.0165440 secs]
[GC 26273K->26272K(34608K), 0.0168730 secs]
[GC 28448K->28447K(34608K), 0.0402030 secs]
[GC 30623K->30622K(34608K), 0.0166760 secs]
[GC 30667K->30648K(34608K), 0.0016900 secs]
[Full GC 30648K->28903K(34608K), 0.1865680 secs]
[GC 36094K->36093K(51824K), 0.0243340 secs]
[GC 39357K->39355K(51824K), 0.0254730 secs]
[GC 42619K->42618K(51824K), 0.0263010 secs]
-1321504640
pjt33@agape:/tmp/jni/$
UPD: посоветовали посмотреть на flatbuffers,
https://github.com/alexkasko/unsafe‑tools
+19
