Validation error: "No validator could be found for type: java.lang.Integer"

Solution 1:

As per the javadoc of NotEmpty, Integer is not a valid type for it to check. It's for Strings and collections. If you just want to make sure an Integer has some value, javax.validation.constraints.NotNull is all you need.

public @interface NotEmpty

Asserts that the annotated string, collection, map or array is not null or empty.

Solution 2:

As the question is asked simply use @Min(1) instead of @size on integer fields and it will work.

Solution 3:

As stated in problem, to solve this error you MUST use correct annotations. In above problem, @NotBlank or @NotEmpty annotation must be applied on any String field only.

To validate long type field, use annotation @NotNull.

Solution 4:

For this type error: UnexpectedTypeException ERROR: We are trying to use incorrect Hibernate validator annotation on any bean property. For this same issue for my Springboot project( validating type 'java.lang.Integer')

The solution that worked for me is using @NotNull for Integer.