Description of problem:

In the following code, the javac in OpenJDK 1.6.0 gets a compilation error, when the Oracle JDK update 25 does not error on it.

/home/andrig/Build/myforkedhibernate4/hibernate-core/hibernate-entitymanager/src/main/java/org/hibernate/ejb/criteria/path/AbstractPathImpl.java:197: invalid inferred types for M; inferred type does not conform to declared bound(s)
inferred: java.util.Map<K,V>
bound(s): java.util.Map<capture#981 of ?,capture#59 of ?>
				return (PluralAttributePath<Y>) get( (MapAttribute<X,?,?>) pluralAttribute );
				                                   ^

The above is the error from the build, and the code in question is line 197 in org.hibernate.ejb.criteria.path.AbstractPathImpl.java in the Entity Manager, and it looks like the following:

 return (PluralAttributePath<Y>) get( (MapAttribute<X,?,?>) pluralAttribute );

The larger methods looks as follows:

/**
         * {@inheritDoc}
         */
        @SuppressWarnings({ "unchecked" })
        public <Y> Path<Y> get(String attributeName) {
                if ( ! canBeDereferenced() ) {
                        throw illegalDereference();
                }

                final Attribute attribute = locateAttribute( attributeName );

                if ( attribute.isCollection() ) {
                        final PluralAttribute<X,Y,?> pluralAttribute = (PluralAttribute<X,Y,?>) attribute;
                        if ( PluralAttribute.CollectionType.MAP.equals( pluralAttribute.getCollectionType() ) ) {
                                return (PluralAttributePath<Y>) get( (MapAttribute<X,?,?>) pluralAttribute );
                        }
                        else {
                                return (PluralAttributePath<Y>) get( (PluralAttribute) pluralAttribute );
                        }
                }
                else {
                        return get( (SingularAttribute<X,Y>) attribute );
                }
        }

As you can see, the error has to do with compiling around the "generics" stuff.

Version-Release number of selected component (if applicable):

[andrig@worklaptop path]$ java -version
java version "1.6.0_22"
OpenJDK Runtime Environment (IcedTea6 1.10.2) (fedora-58.1.10.2.fc15-x86_64)
OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode)

How reproducible:

Every time.

Steps to Reproduce:
1.clone the Hibernate 4 Git repository.
2.run ./gradlew -x text clean build
3.See the error...
  
Actual results:

Compilation error shown above in the description.

Expected results:

Should compile cleanly as it does with Oracle JDK 1.6.0_25

Additional info: