Validation groups in Spring Boot - Step-by-Step Execution

Concept Flow - Validation groups

Define Validation Groups Interfaces

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Annotate Bean Fields with Groups

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Trigger Validation with Specific Group

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Validation Framework Checks Only That Group's Constraints

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Return Validation Result (Errors or Success)

Validation groups let you organize validation rules into sets and apply only the needed set when validating an object.

Execution Sample

Spring Boot

public interface CreateGroup {}
public interface UpdateGroup {}

public class User {
  @NotNull(groups = CreateGroup.class)
  private String name;
}

// Validate with CreateGroup

Defines two groups and applies @NotNull only when validating with CreateGroup.

Execution Table

Step	Action	Validation Group	Field Checked	Constraint	Result
1	Start validation	CreateGroup	name	@NotNull	Field 'name' must not be null
2	Field 'name' is null	CreateGroup	name	@NotNull	Validation fails
3	Start validation	UpdateGroup	name	@NotNull	Constraint not checked
4	Field 'name' is null	UpdateGroup	name	No constraint	Validation passes
5	End validation	-	-	-	Validation result returned

💡 Validation stops after checking constraints for the specified group only.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
validationGroup	-	CreateGroup	CreateGroup	UpdateGroup	UpdateGroup	-
field 'name'	null	null	null	null	null	null
validationResult	-	pending	fail	pending	pass	final result

Key Moments - 2 Insights

Why does validation fail with CreateGroup but pass with UpdateGroup when the field is null?

Because the @NotNull constraint is only applied to CreateGroup (see execution_table rows 1-4). UpdateGroup does not check this constraint.

Can multiple groups be validated at once?

Yes, you can specify multiple groups to validate, and all constraints in those groups will be checked.

Visual Quiz - 3 Questions

Look at the execution table, what is the validation result at Step 2 when validating with CreateGroup?

A Validation fails

B Constraint not checked

C Validation passes

D Validation pending

💡 Hint

Check the 'Result' column at Step 2 in the execution_table.

At which step does the validation framework skip the @NotNull constraint?

A Step 1

B Step 2

C Step 3

D Step 5

💡 Hint

Look for 'Constraint not checked' in the execution_table.

If the field 'name' was not null, how would the validation result change at Step 2?

A Validation would still fail

B Validation would pass

C Constraint would be ignored

D Validation would be pending

💡 Hint

Refer to the 'Constraint' and 'Result' columns in Step 2 of the execution_table.

Concept Snapshot

Validation groups let you assign constraints to named groups.
When validating, specify which group(s) to apply.
Only constraints in those groups run.
Useful to reuse the same bean with different rules.
Example: @NotNull(groups=CreateGroup.class) applies only when CreateGroup is validated.

Full Transcript

Validation groups in Spring Boot let you organize validation rules into sets called groups. You define interfaces as group names, then assign constraints to those groups on your bean fields. When you validate an object, you specify which group to use. The validation framework then checks only the constraints in that group. For example, a field might be @NotNull only for the CreateGroup, so if you validate with CreateGroup and the field is null, validation fails. But if you validate with UpdateGroup, that constraint is ignored and validation passes. This helps reuse the same bean with different validation rules depending on the context.