How to call Scala curry functions from Java with Generics

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A Scala code has a retry mechanism which is based on currying function:

object RetryUtil {

  def retry[T](retry: Int, timeout: FiniteDuration)(exc: => T): T = {

I want to call this code from Java (8), which use generics:

public class SuperService {

    public <T> T call(Data<T> data) {
     // I want to call internalCall from here, with the Scala retry mechanism from before.

    private <T> T internalCall(DataWithResult<T> data) {

How should it be done?




private <T> T internalCall(TransactionWithResult<T> data) {
  return null;

private void internalCall2(TransactionWithoutResult data) {


public <T> T call(Data<T> data) {
  RetryUtil.retry(3, new FiniteDuration(1, TimeUnit.MINUTES), () -> { internalCall2(data); return null; });

  return RetryUtil.retry(3, new FiniteDuration(1, TimeUnit.MINUTES), () -> internalCall(data));

Parameters from multiple parameter lists in Scala should be seen in Java as parameters of a single parameter list.

Scala and Java functions should be interchangeable (since Scala 2.12)

How to use Java lambdas in Scala (

By-name parameters => T should be seen as no-arg functions () => T.

I assumed that Data implements TransactionWithResult and TransactionWithoutResult, so Data can be used where TransactionWithResult or TransactionWithoutResult is expected, otherwise the code should be fixed.

Source: stackoverflow