Spring MVC Custom Validator

spring-mvc-java/src/main/java/com/baeldung/customvalidator/ContactNumberConstraint.java

@@ -0,0 +1,22 @@
+package com.baeldung.customvalidator;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import javax.validation.Constraint;
+import javax.validation.Payload;
+
+@Documented
+@Constraint(validatedBy = ContactNumberValidator.class)
+@Target( { ElementType.METHOD, ElementType.FIELD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface ContactNumberConstraint {
+
+    String message() default "Invalid phone number";
+    Class<?>[] groups() default {};
+    Class<? extends Payload>[] payload() default {};
+    
+}