Overwriting default Hibernate Validator messages

I want to overwrite the default Hibernate Validator messages in a server faces web app, so I read this part of the documentation: https://docs.jboss.org/hibernate/validator/5.0/reference/en-US/html/chapter-message-interpolation.html#section-message-interpolation

I created two files inside the src/ folder: ValidationMessages.properties and ValidationMessages_de_DE.properties. The file contents are:

javax.validation.constraints.AssertFalse.message = must be false
javax.validation.constraints.AssertTrue.message  = must be true
javax.validation.constraints.DecimalMax.message  = must be less than ${inclusive == true ? 'or equal to ' : ''}{value}
javax.validation.constraints.DecimalMin.message  = must be greater than ${inclusive == true ? 'or equal to ' : ''}{value}
javax.validation.constraints.Digits.message      = numeric value out of bounds (<{integer} digits>.<{fraction} digits> expected)
javax.validation.constraints.Future.message      = must be in the future
javax.validation.constraints.Max.message         = must be less than or equal to {value}
javax.validation.constraints.Min.message         = must be greater than or equal to {value}
javax.validation.constraints.NotNull.message     = may not be null
javax.validation.constraints.Null.message        = must be null
javax.validation.constraints.Past.message        = must be in the past
javax.validation.constraints.Pattern.message     = must match "{regexp}"
javax.validation.constraints.Size.message        = size must be between {min} and {max}

org.hibernate.validator.constraints.CreditCardNumber.message = invalid credit card number
org.hibernate.validator.constraints.Email.message            = not a well-formed email address
org.hibernate.validator.constraints.Length.message           = length must be between {min} and {max}
org.hibernate.validator.constraints.NotBlank.message         = may not be empty
org.hibernate.validator.constraints.NotEmpty.message         = may not be empty
org.hibernate.validator.constraints.Range.message            = must be between {min} and {max}
org.hibernate.validator.constraints.SafeHtml.message         = may have unsafe html content
org.hibernate.validator.constraints.ScriptAssert.message     = script expression "{script}" didn't evaluate to true
org.hibernate.validator.constraints.URL.message              = must be a valid URL
org.hibernate.validator.constraints.br.CNPJ.message          = invalid Brazilian corporate taxpayer registry number (CNPJ)
org.hibernate.validator.constraints.br.CPF.message           = invalid Brazilian individual taxpayer registry number (CPF)
org.hibernate.validator.constraints.br.TituloEleitor.message = invalid Brazilian Voter ID card number

I am using a german version of Windows, so the messages are by default in german. After creating the files they should be in english, but they are still in german.

What am I doing wrong?

Okay, the correct folder is /src/main/java/.