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POReturning null from native methods using JNI
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copied!<p>I have some native code which returns a jbyteArray (so byte[] on the Java side) and I want to return null. However, I run into problems if I simply return 0 in place of the jbyteArray.</p> <p>Some more information: The main logic is in Java, the native method is used to encode some data into a byte stream. don;t ask.. it has to be done like this. Recently, the native code had to be changed a bit and now it runs horribly horrible slow. After some experimentation, which included commenting out all code in the native method before the return, it turns out that returning 0 causes the slowdown. When returning an actual jbyteArray, everything is fine.</p> <p>Method signatures for my code:</p> <p>On the C++ side:</p> <pre><code>extern "C" JNIEXPORT jbyteArray JNICALL Java_com_xxx_recode (JNIEnv* env, jclass java_this, jbyteArray origBytes, jobject message) </code></pre> <p>On the Java side:</p> <pre><code>private static native byte[] recode(byte[] origBytes, Message message); </code></pre> <p>The native code looks something like this:</p> <pre><code>jbyteArray javaArray; if (error != ERROR) { // convert to jbyteArray javaArray = env->NewByteArray((jsize) message.size); env->SetByteArrayRegion(java_array, 0, message.size, reinterpret_cast<jbyte*>(message.buffer())); if (env->ExceptionOccurred()) { env->ExceptionDescribe(); error = ERROR; } } if (error == ERROR) { return 0; // Does NOT work - doesn't crash, just slows everything down horrible. } else { return javaArray; // Works perfectly. } </code></pre> <p>Does anyone know of any reasons that this could happen? Is it valid to return NULL from a native method in place of a jbyteArray, or is there another procedure to return null back to Java. Unfortunately, I had no luck on Google.</p> <p>Thanks!</p> <p>EDIT: Added additional information.</p>

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