[LANG-1190] TypeUtils.isAssignable throws NullPointerException when fromType has type variables and toType generic superclass specifies type variable - ASF JIRA

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Details

Type: Bug
Status: Closed
Priority: Major
Resolution: Fixed
Affects Version/s: 3.4
Fix Version/s: 3.5
Component/s: lang.reflect.*
Labels:
None

Description

import static org.apache.commons.lang3.reflect.TypeUtils.*;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Type;
import java.util.ArrayList;

public class Demonstration {

    public static <U> Iterable<U> someMethod() { return null; }
    
    public static class WorkingClass extends ArrayList { }
    public static class FailingClass extends ArrayList<Object> { }
    
    
    public static void main(String[] args) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        Type fromType = Demonstration.class.getDeclaredMethod("someMethod").getGenericReturnType();
        Type workingToType = wildcardType().withLowerBounds(WorkingClass.class).build();
        Type failingToType = wildcardType().withLowerBounds(FailingClass.class).build();
        
        System.out.println(fromType);
        System.out.println(workingToType);
        System.out.println(failingToType);
        
        System.out.println(isAssignable(fromType, workingToType));
        System.out.println(isAssignable(fromType, failingToType));
    }
}