Compilation error with JDK8 and Guava (original) (raw)

Remi Forax forax at univ-mlv.fr
Tue Apr 2 02:45:42 PDT 2013

On 04/02/2013 08:50 AM, Olivier Bourgain wrote:

Hi all,

I tried to compile my project at work with the JDK 8 and I get a compilation error. The simplest example which I was able to extract is the following. It uses Guava 1.14.0.1.

Hi Olivier, could you test with b83 because it looks like a bug that was fixed recently.

cheers, Rémi

import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import com.google.common.collect.Lists; public class TestCase { public static <K, V> Map<K, V> reverseMap(List<Map.Entry<K, V>> list) { return toMap(Lists.reverse(list)); } public static <K, V> Map<K, V> toMap(List<Map.Entry<K, V>> list) { Map<K, V> result = new LinkedHashMap<>(); for (Map.Entry<K, V> entry : list) result.put(entry.getKey(), entry.getValue()); return result; } } The compilation error is : » javac -cp lib/guava-14.0.1.jar src/TestCase.java src/TestCase.java:9: error: method toMap in class TestCase cannot be applied to given types; return toMap(Lists.reverse(list)); ^ required: List<Entry<K#1,V#1>> found: List<Entry<K#2,V#2>> reason: inferred type does not conform to equality constraint(s) inferred: Entry<Object,Object> equality constraints(s): Entry<Object,Object>,Entry<K#2,V#2> where K#1,V#1,K#2,V#2 are type-variables: K#1 extends Object declared in method <K#1,V#1>toMap(List<Entry<K#1,V#1>>) V#1 extends Object declared in method <K#1,V#1>toMap(List<Entry<K#1,V#1>>) K#2 extends Object declared in method <K#2,V#2>reverseMap(List<Entry<K#2,V#2>>) V#2 extends Object declared in method <K#2,V#2>reverseMap(List<Entry<K#2,V#2>>) 1 error

The java version is : java version "1.8.0-ea" Java(TM) SE Runtime Environment (build 1.8.0-ea-b82) Java HotSpot(TM) Server VM (build 25.0-b23, mixed mode) The same code compiles without error with Java 1.7. Olivier Bourgain

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