Tag: classcastexception

REST api with only 1 object java

This code makes use of JSON-simple for connecting to an api: Nothing get sent out though. Only warning is this: Answer Casting to a string is the solution.

ClassCastException “Parent cannot be cast to class…are in unnamed module of loader ‘app’ ” with Java Generics and inheritance

classcastexception generics inheritance java

I´m currently facing a problem with generics in Java. I need to return a parent instance casted to the child. The sample below shows what I´m trying to achieve. This code does not run through and produces this exception instead: class com.generics.GenericTest$Parent cannot be cast to class com.generics.GenericTest$ChildEntity (com.generics.GenericTest$Parent and com.generics.GenericTest$ChildEntity are in unnamed module of loader ‘app’) java.lang.ClassCastException: class

Java strange class cast exception

classcastexception functional-programming interface java

Could anyone help me understand why in 1 situation I do not have ClassCastException? At least String::trim is not a MagicFunction. Answer So, method references (like String::trim) are a bit weird; unlike most expressions in Java, they don’t really have a type of their own. Something like this: won’t even compile, because it doesn’t give the compiler enough information about

Returning result of count native query using EntityManager in Java?

classcastexception entitymanager integer java

I have the following SQL Query : I am trying to write this in java : However I get this exception: How can I solve this? Answer You can also use Number and call intValue():