[iulianbudau]

Motivation and Context

TableSchema.fromClass / immutable schema creation fails for Lombok-style @DynamoDbImmutable models when a field such as __encryption_keyId produces getter get__encryption_keyId() and fluent builder __encryption_keyId(...). ImmutableIntrospector only stripped a get prefix when the next character was uppercase, so the property key stayed get__encryption_keyId and did not match the builder. The equivalent @DynamoDbBean path already maps the attribute as __encryption_keyId via JavaBeans introspection.
Fixes #5589.

Modifications

• In ImmutableIntrospector.normalizeGetterName, the get branch also strips when the character after get is _ or $, preserving existing lowercasing/suffix behavior (getId → id, getURL → uRL, getfoo → getfoo).
• Prefer a valid builder match on the normalized name; for get_ / get$ getters only, fall back to the original getter name if no valid normalized builder exists (legacy pairing). Ordinary getX / isX stripping does not use that fallback.
• normalizeSetterName, the is branch, discovery, ignore/transient handling, and unmatched/leftover validation behavior are unchanged aside from using the resolved property name.
• Tests (handwritten models; no Lombok dependency): introspector coverage for normalized/legacy _ and $, ambiguous both-builders, and getURL/getfoo; schema round-trips via itemToMap / mapToItem plus a @DynamoDbBean control for attribute __encryption_keyId.

Testing

Tests added

• Updates to ImmutableIntrospectorTest
• New ImmutableLeadingUnderscoreAttributeTest (normalized/legacy _ and $ schema round-trips; bean control)
• Tests executed and passed locally

Test Coverage Matrix

Scenario	Done	Comments if Not Done
1. Different TableSchema Creation Methods
a. TableSchema.fromBean(Customer.class)	[x]	Bean control via TableSchema.fromBean(UnderscoreBean.class) in ImmutableLeadingUnderscoreAttributeTest; focused + module tests passed.
b. TableSchema.fromImmutableClass(Customer.class) for immutable classes	[ ]	Immutable cases used TableSchema.fromClass (same immutable introspection path); fromImmutableClass not invoked explicitly.
c. TableSchema.documentSchemaBuilder().build()	[ ]	Not applicable to this immutable getter-normalization fix.
d. StaticTableSchema.builder(Customer.class)	[ ]	Not applicable; static schemas do not use ImmutableIntrospector naming.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
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• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license