Problem with creating java anonymous class with generics in scala

Question

For example I have following Java inteface

public interface Test<T,M> {
       public M get(T t);
}

if I whant create ananymoys class in java with this interface

val t = new Test[Int,Boolean](){
     def get(t: Boolean) = 0
}

I have following error

Scala.scala:15: error: scal.test.example.Test does not take type parameters val t = new Test[Int,Boolean](){

Randall Schulz · Accepted Answer · 2010-09-21 17:16:49Z

4

Enclosing your Scala code in an object for separate compilation and correcting the order of the type parameters:

object TestI {
    val t = new Test[Boolean,Int]() {
        def get(t: Boolean) = 0
    }
}

... I do not get any compilation errors.

answered Sep 21, 2010 at 17:16

Randall Schulz

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4 Comments

Alexander Kuznetsov Over a year ago

I tried this and get the same error. I use maven for compilation with scala compile plugin with version 2.6.1 and scala 2.8

Randall Schulz Over a year ago

I suspect either your Java interface is not in the same package as your Scala class, you failed to import that interface, Maven isn't compiling the Java first, the Java-generated .class files aren't in the class-path during Scala compilation or some combination thereof.

Alexander Kuznetsov Over a year ago

This is not a problem becouse the following code works fine val t = new Test() { def get(t: Any) = null } That is you version of scala?

Randall Schulz Over a year ago

I should have noticed that your diagnostic was not about an undefined Test, but rather about a Test that was being used in a manner not consistent with its definition.

Alexander Kuznetsov · Accepted Answer · 2010-09-21 19:39:17Z

2

It was old version of scala 2.6.1. It was installed by default from maven archity for scala projects. Now I upgraded version to 2.8.0 and problem was solved. For old version your need to scpecify the version of java.

answered Sep 21, 2010 at 19:39

Alexander Kuznetsov

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