Scala - reflectively invoke private static method from Java

Question

I'm trying to take a private static method from a Java class and invoke it in Scala. Here's the code I have so far:

val blockClass = classOf[Block]
val aMethod: Method = blockClass.getDeclaredMethod("a", Integer.TYPE, classOf[String], classOf[Block])
aMethod.setAccessible(true)

aMethod.invoke(null, 145, "anvil", anvilPatch)

When I try to compile this, however, I get this error:

Error: the result type of an implicit conversion must be more specific than AnyRef
aMethod.invoke(null, 145, "anvil", null)
                     ^

That 145 is supposed to be a Java int, and Integer.TYPE is the only thing I could think of to get a Java int.

Any ideas?

Alexey Romanov · Accepted Answer · 2015-09-28 07:20:51Z

1

Not sure why the error happens, but it can be fixed simply by casting 145 to AnyRef (which is the same as Object) explicitly:

aMethod.invoke(null, 145.asInstanceOf[AnyRef], "anvil", anvilPatch)

answered Sep 28, 2015 at 7:20

Alexey Romanov

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marstran · Accepted Answer · 2015-09-28 07:23:20Z

0

Instead of using Integer.TYPE, try using classOf[Int]. This will get you the class object of Scala's Int type.

val aMethod: Method = blockClass.getDeclaredMethod("a", classOf[Int], classOf[String], classOf[Block])

answered Sep 28, 2015 at 7:23

marstran

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