CODEWITHSUNDEEP
javajava-native-interface
Dan Berindei
Dan Berindei

Reputation: 7204

Checking if a Java object is of an array type in JNI

Say I have a MyClass class in Java, is there a way to check in JNI that a jobject is a MyClass[][]?

My initial idea was to use env->IsInstanceOf(myobj, myArrayClass), but calling env->FindClass("[MyClass") throws a NoClassDefFoundError.

Upvotes: 5

Views: 3182

Answers (2)

Andriy Tylychko
Andriy Tylychko

Reputation: 16286

I know this question is old but...

To find a class of your array, use:

env->FindClass("[[Lmy/package/MyClass;")

Upvotes: 3

Rob Heiser
Rob Heiser

Reputation: 2862

A little rusty on JNI, but a couple of things:

Call FindClass() on your fully qualified classname, using a "/" as a separator instead of dots. So, for instance if your class is "my.package.MyClass", you would call env->FindClass("my/package/MyClass")

Since you have a two-dimensional array of your object type, you need to call env->GetObjectArrayElement() twice; once to get a row and another time to get a distinct element. Then you can call env->IsInstanceOf() on that element. Make sure you look up the correct signatures for these JNI calls, I've left them as an exercise for the reader :)

Upvotes: 1

Related Questions