Can a Java class implement a C++ interface

Question

Is it possible to a Java class to implement a C++ interface (interface meaning a full abstract class)? Where can I read more about?

Answer 1

Yes, you have to use JNI .

Here's a tutorial from Sun / Oracle

Answer 2

Not directly, no. However, you can create a C++ implementation of that interface that simply delegates to a Java implementation via JNI. See the JNI Specification for more details.

Answer 3

Not in the general sense, no. C++ classes do not exist in the compiled binary the vast majority of the time.

Answer 4

Besides JNI there's another technology named JNA . It seems to be simpler (no need to create C/C++ stub code).

Answer 5

Support for overriding virtual C++ methods is planned in BridJ (a JNA alternative that supports C++), but it's not there yet.

Update: As of version 0.4 , BridJ supports implementing C++ interfaces from Java :

Consider the following C++ class :

#ifndef TEST_EXPORTS
#define TEST_EXPORTS
#endif
class TEST_EXPORTS TestClass {
public:
    virtual int add(int a, int b);
};

You'd bind this class from Java with these BridJ bindings :

public class TestClass extends CPPObject { 
    @Virtual(0) 
    public native int add(int a, int b); 
}; 

And would be able to subclass your C++ class from Java very naturally :

TestClass test = new TestClass() { 
    @Override 
    public int add(int a, int b) { 
        return a + b; 
    } 
}; 

Answer 6

Java class can implement Java interface. Java/C++ communication is done using JNI.