core/src/com/google/inject/TypeLiteral.java
public TypeLiteral<?> getReturnType(Method method) {
    checkArgument(
        method.getDeclaringClass().isAssignableFrom(rawType),
        "%s is not defined by a supertype of %s",
        method,
        type);
    return resolve(method.getGenericReturnType());
  }
public TypeLiteral<?> getReturnType(Method method) {
    checkArgument(
        method.getDeclaringClass().isAssignableFrom(rawType),
        "%s is not defined by a supertype of %s",
        method,
        type);
    return resolve(method.getGenericReturnType());
  }
public TypeLiteral < ? > getReturnType ( Method method ) { checkArgument ( method . getDeclaringClass ( ) . isAssignableFrom ( rawType ) , "%s is not defined by a supertype of %s" , method , type ) ; return resolve ( method . getGenericReturnType ( ) ) ; }
Returns the resolved generic return type of {@code method}.

@param method a method defined by this or any supertype.
@since 2.0
Returns the resolved generic return type of { @code method } .