Avoid huge data copy from C++ to Java

Question

I have an application with high perf. requirements.

The problem at hand is that I need to invoke some Java API to copy a native (C++) array into disk, from a Java API. The data is going to be big, so I want to avoid copies from C to Java land. I want just to pass a reference to the data in some way and serialize that data

The problem is that if I send a byte[] the Java GC will delete it and we do not want this to happen.

I thought of wrapping my native array data in a class/struct in C++ but at the end I need a byte[] stream or similar in the Java side. Is there a way I can cast some reference to some data in C++ to byte[] in Java, and immediately after that leave that memory alone, avoiding the GC to recycle it?

• Danh: Why don't you do it in C++ instead?
• Germán Diago: Because I need to call an already implemented Java API that provides much more functionality. It does not only save things, it adds it into a database and does more stuff.
• Galik: Is there a reason you can't maintain a reference to your byte[] in Java to prevent the Garbage Collector from claiming it?
• Kayaman: See related questions: stackoverflow.com/questions/1491519/…, stackoverflow.com/questions/15130283/java-and-c-shared-memory, stackoverflow.com/questions/15414753/…, stackoverflow.com/questions/904492/…
• Wilfredo Pomier: If both java and c++ code are running inside the same process, and if you can modify the java source then you can create a method in java to allocate and return a memory chunck, fill it in C++ and call another java method to process it in java. C++ is far more flexible than java. Now, if they aren't in the same process, then using Shared Memory or Memory-mapped files can be your solution.