CODEWITHSUNDEEP
scala
joshuaar
joshuaar

Reputation: 87

Scala: Why does classOf[Int].cast(1) throw a java.lang.ClassCastException?

When I run the following on the Scala 2.10 REPL:

classOf[Int].cast(1)

I get the following error:

java.lang.ClassCastException: Cannot cast java.lang.Integer to int
at java.lang.Class.cast(Class.java:3176)
at .<init>(<console>:18)
...

Why is this happening?

Upvotes: 0

Views: 299

Answers (1)

Madoc
Madoc

Reputation: 5919

This is because of autoboxing. It is a common feature, not only found in Scala, but also in Java. The int value needs to be passed to the cast method as an object. But an int is not an object, so the compiler introduces a conversion to an instance of java.lang.Integer. And that's a different type than int, it's as simple as that.

This one should work:

classOf[java.lang.Integer].cast(1)

Upvotes: 2

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