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https://issues.apache.org/jira/browse/GROOVY-11615?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17944963#comment-17944963
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Saravanan edited comment on GROOVY-11615 at 4/16/25 7:06 AM:
-------------------------------------------------------------
You are right, it works in 5.x, but this does not work (I am not able to figure
out a pattern here, sorry)
{code:java}
import com.google.common.collect.ImmutableMap;
import java.util.stream.Collectors;
public class Interfaces {
public String myThing() {
var myArray = ImmutableMap.of("123", "1354");
// This call will fail.
// Incompatible generic argument types. Cannot assign
java.util.Map<java.lang.Integer, java.lang.Object>
// to: java.util.Map<java.lang.Integer, java.lang.String>
// To make it work change it to
// Map<Integer, String> mySet =
myArray.entrySet().stream().map(entry ->
// String.format(entry.getKey() + "-" + entry.getValue())
// ).collect(Collectors.<String, Integer,
String>toMap(String::length, value -> value));
Map<Integer, String> mySet = myArray.entrySet().stream().map(entry ->
String.format(entry.getKey() + "-" + entry.getValue())
).collect(Collectors.toMap(String::length, value -> value));
}
}
{code}
was (Author: chavan77):
You are right, it works in 5.x, but this does not work (I am not able to figure
out a pattern here, sorry)
{code:java}
import com.google.common.collect.ImmutableMap;
import java.util.stream.Collectors;
public class Interfaces {
public String myThing() {
var myArray = ImmutableMap.of("123", "1354");
// This call will fail.
// Incompatible generic argument types. Cannot assign
java.util.Map<java.lang.Integer, java.lang.Object>
// to: java.util.Map<java.lang.Integer, java.lang.String>
// To make it work change it to
// Map<Integer, String> mySet =
myArray.entrySet().stream().map(entry ->
// String.format(entry.getKey() + "-" + entry.getValue())
// ).collect(Collectors.<String, Integer,
String>toMap(String::length, value -> value));
Map<Integer, String> mySet = myArray.entrySet().stream().map(entry ->
String.format(entry.getKey() + "-" + entry.getValue())
).collect(Collectors.<String, Integer, String>toMap(String::length,
value -> value));
}
}
{code}
> Groovy has trouble type inferencing for Collections. The offender is
> Collectors.asBlah set of methods. It needs the generic type <A.Y.X> to be
> added explicitly
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: GROOVY-11615
> URL: https://issues.apache.org/jira/browse/GROOVY-11615
> Project: Groovy
> Issue Type: Bug
> Components: Static Type Checker
> Affects Versions: 4.0.24
> Reporter: Saravanan
> Priority: Minor
>
> {code:java}
> public class Interfaces {
> public String myThing() {
> var myArray = Arrays.asList("123", "1354");
> var mySet = myArray.stream().collect(Collectors.toSet());
>
> // This call will fail
> // Failed to find class method 'getBytes(java.lang.Object)' or
> // instance method 'getBytes()' for the type: java.lang.String
> // To make it work change the previous line to
> // var mySet =
> myArray.stream().collect(Collectors.<String>toSet());
> mySet.forEach(String::getBytes);
> }
> }{code}
> Most Collectors.<methods> need a fully qualified type for the generic
> parameter, without which the compile will fail (sometimes detect an Object
> type instead of the right one)
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