+# elif defined(WITH_JAVA_RUNTIME_LIBRARY_OPENJDK)
+
+ TRACEJNICALLS(("jni_GetDirectBufferCapacity(env=%p, buf=%p)", env, buf));
+
+ java_nio_Buffer jnb(buf);
+
+ if (!builtin_instanceof(jnb.get_handle(), class_sun_nio_ch_DirectBuffer))
+ return -1;
+
+ jlong capacity = jnb.get_capacity();
+
+ return capacity;
+
+# else
+# error unknown classpath configuration
+# endif
+