Dump all Java strings using JVMTI

heapIterator.c

#include <jvmti.h>
#include <stdio.h>
#include <wchar.h>

static jvmtiEnv* jvmti;

JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM* vm, void* reserved) {
    (*vm)->GetEnv(vm, (void**)&jvmti, JVMTI_VERSION_1_0);

    jvmtiCapabilities capabilities = {0};
    capabilities.can_tag_objects = 1;
    jvmtiError err = (*jvmti)->AddCapabilities(jvmti, &capabilities);

    return JNI_VERSION_1_4;
}

jint JNICALL stringCallback(jlong class_tag, jlong size, jlong* tag_ptr,
                            const jchar* value, jint value_length, void* user_data) {
    wprintf(L"%.*s\n", value_length, value);
    return 0;
}

JNIEXPORT void JNICALL Java_HeapIterator_printStrings(JNIEnv* env, jclass cls) {
    jvmtiHeapCallbacks callbacks = {NULL, NULL, NULL, NULL, stringCallback};
    (*jvmti)->IterateThroughHeap(jvmti, 0, NULL, &callbacks, NULL);
}

HeapIterator.java

public class HeapIterator {

    static {
        System.loadLibrary("heapIterator");
    }

    private static native void printStrings();

    public static void main(String[] args) throws Exception {
        printStrings();
    }
}