scala-java-interop

Consider the following Scala code: package scala_java object MyScala { def setFunc(func: Int => String) { func(10) } } Now in Java, I would have liked to use MyScala as: package scala_java; public class MyJava { public static void main(String [] args) { MyScala.setFunc(myFunc); // This line gives an error } public static String myFunc(int someInt) { return String.valueOf(someInt); } } However, the above does not work (as expected since Java does not allow functional programming). What is the easiest workaround to pass a function in Java? I would like a generic solution that works with

How to convert Scala's scala.List into Java's java.util.List ? Daniel C. Sobral Scala List and Java List are two different beasts, because the former is immutable and the latter is mutable. So, to get from one to another, you first have to convert the Scala List into a mutable collection. On Scala 2.7: import scala.collection.jcl.Conversions.unconvertList import scala.collection.jcl.ArrayList unconvertList(new ArrayList ++ List(1,2,3)) From Scala 2.8 onwards: import scala.collection.JavaConversions._ import scala.collection.mutable.ListBuffer asList(ListBuffer(List(1,2,3): _*)) val x: java

I have a Scala object that I need to use in a Java class. Here's the Scala object object Person { val MALE = "m" val FEMALE = "f" } How can I use this Scala object in Java? I have tried the following so far without success (compile errors): Person.MALE() //returns a String which is useless as I want the actual Person object Petr Pudlák Use Person$.MODULE$ . See also How can I pass a Scala object reference around in Java? Singletons as Synthetic classes in Scala? Edit : A working example (I checked, it compiles and works): Scala: object Person { val MALE = "m"; } Java counterpart: public class

What is the difference between == and .equals() in Scala, and when to use which? Is the implementation same as in Java? EDIT: The related question talks about specific cases of AnyVal . The more general case is Any . Didier Dupont You normally use == , it routes to equals , except that it treats null s properly. Reference equality (rarely used) is eq . == is a final method, and calls .equals , which is not final. This is radically different than Java, where == is an operator rather than a method and strictly compares reference equality for objects. TL;DR Override equals method to compare

I'm writing some Scala code which uses the Apache POI API. I would like to iterate over the rows contained in the java.util.Iterator that I get from the Sheet class. I would like to use the iterator in a for each style loop, so I have been trying to convert it to a native Scala collection but will no luck. I have looked at the Scala wrapper classes/traits, but I can not see how to use them correctly. How do I iterate over a Java collection in Scala without using the verbose while(hasNext()) getNext() style of loop? Here's the code I wrote based on the correct answer: class IteratorWrapper[A]