java.lang.ClassCastException: class org.json.JSONObject$Null cannot be cast to class java.lang.String (org.json.JSONObject$Null is in unnamed module of loader 'app'; java.lang.String is in module java.base of loader 'bootstrap')

[mpet]

java.lang.ClassCastException: class org.json.JSONObject$Null cannot be cast to class java.lang.String (org.json.JSONObject$Null is in unnamed module of loader 'app'; java.lang.String is in module java.base of loader 'bootstrap')

[erosb]

Hello, it seems your schema json goes through plenty of transformations, and somewhere a "$schema":null property is added, on which the exception is thrown (which is quite reasonable, since the value of $schema must be a string.

Maybe after this line JSONObject jsonSchema = new JSONObject(new JSONTokener(schemaNode.toString())); you could remove it programmatically, like jsonSchema.remove("$schema"); so that the SchemaLoader receives a clean input.

[mpet]

Hello,
Thanks for reply. Seems like I have null for others too. Do you know the reason for these null?

[erosb]

I don't know, since it gets added before the validator library is called.