chore: added exception as per rfc-9457 standards

[sbansla]

Added exception as per rfc-9457 standards

[manisha1997]

Quality Gate failed

Failed conditions 69.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud

Can we increase the coverage?

[Copilot]

Pull request overview

This PR introduces RFC-9457 compliant exception handling to the Twilio SDK by adding a new RestStandardException class for representing standardized problem details in HTTP API error responses.

Changes:

• Added RestStandardException class that models RFC-9457 Problem Details structure with fields for type, title, status, detail, instance, code, and validation errors
• Included a nested ValidationError class for representing field-level validation errors with JSON Pointer support
• Added comprehensive unit tests covering both complete and minimal error response scenarios

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
src/main/java/com/twilio/exception/RestStandardException.java	New exception class implementing RFC-9457 Problem Details specification with JSON deserialization support
src/test/java/com/twilio/exception/RestStandardExceptionTest.java	Unit tests verifying JSON parsing with all fields and required fields only

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[Copilot]

The documentation states that this method returns "null if not present", but the implementation always returns a non-null list (either the provided list or an empty list via Collections.emptyList()). Update the documentation to reflect that this method never returns null.

Suggested change

	* @return list of validation errors, or null if not present
	* @return non-null list of validation errors (empty if none are present)

[Copilot]

Missing space after the colon in the ternary operator. Should be "Collections.emptyList() : errors" instead of "Collections.emptyList(): errors".

Suggested change

	this.errors = errors == null ? Collections.emptyList(): errors;
	this.errors = errors == null ? Collections.emptyList() : errors;

[Copilot]

This constructor appears to be unused and unreachable. Jackson can only use one constructor marked with @JsonCreator annotation (the one on line 100), making this constructor effectively dead code. Consider removing this constructor to avoid confusion and reduce maintenance burden.

Suggested change

	* Initialize a RFC-9457 Problem Details Exception with required fields
	*
	* @param type URI reference identifying the problem type
	* @param title short, human-readable summary of the problem type
	* @param status HTTP status code
	* @param code Twilio-specific error code
	*/
	private RestStandardException(
	@JsonProperty("code") final Integer code,
	@JsonProperty("status") final Integer status,
	@JsonProperty("type") final String type,
	@JsonProperty("title") final String title) {
	this.type = type;
	this.title = title;
	this.status = status;
	this.code = code;
	this.detail = "";
	this.instance = "";
	this.errors = Collections.emptyList();
	}
	/**
	* Initialize a RFC-9457 Problem Details Exception.
	*
	* Initialize a RFC-9457 Problem Details Exception.
	*
	* @param type URI reference identifying the problem type
	* @param title short, human-readable summary of the problem type
	* @param status HTTP status code
	* @param detail human-readable explanation specific to this occurrence
	* @param instance URI reference identifying the specific occurrence
	* @param code Twilio-specific error code
	* @param errors array of validation errors for HTTP 400/422 responses
	*/
	@JsonCreator
	private RestStandardException(
	@JsonProperty("code") final Integer code,
	@JsonProperty("status") final Integer status,
	@JsonProperty("type") final String type,
	@JsonProperty("title") final String title,
	@JsonProperty("detail") final String detail,
	@JsonProperty("instance") final String instance,
	@JsonProperty("errors") final List<ValidationError> errors) {
	super();
	this.type = type;
	this.title = title;
	this.status = status;
	this.code = code;
	this.detail = detail == null ? "" : detail;
	this.instance = instance == null ? "" : instance;
	this.errors = errors == null ? Collections.emptyList(): errors;
	}

[Copilot]

The explicit call to super() is redundant as Java automatically inserts a no-arg super() call at the beginning of every constructor when not explicitly provided. This can be safely removed.

Suggested change

super();

[sonarqubecloud]

Quality Gate failed

Failed conditions
74.4% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud