Question

I have a list of nodes. This nodes are a data class I defined by myself. Each node has a data field of the type Object. Now I want to find the node in a list of nodes that has the parameter object in the data field. I wrote this method, because I wanted to first compare if the two objects (the parameter and the object in the data field) are of the same type:

public Node getnNodeByData(Object obj) {
    for (Node node : nodes) {
        if (node.getData() instanceof obj.getClass()) {

        }
    }
}

Unfortunately this condition does not work:

Incompatible operand types boolean and Class<capture#1-of ? extends Graph>

I don’t really know why this is a problem. How can I make this working?

Answer 1

No, you need to use Class.isInstance(Object). The instanceof keyword does not expect an object of type Class, but only the name of the class directly — but Class.isInstance is basically analogous.