th:checkedでエラーが発生する（プロパティまたはフィールドがnullで見つかりません）

前提・実現したいこと

thymeleafのチェックボックスの値をcontrollerのPutMappingで受け取りたいです。
が、GetMappingの段階でつまずいています。
プロパティまたはフィールドの「checks」がnullで見つかりませんとエラーが発生しますが、原因かわかりません。。

発生している問題・エラーメッセージ

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "settingEntity.checks.contains(lstWorks.id)" (template: "setting" - line 37, col 43)] with root cause

org.springframework.expression.spel.SpelEvaluationException: EL1007E: Property or field 'checks' cannot be found on null
	at org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:213) ~[spring-expression-5.3.10.jar:5.3.10]
	at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:104) ~[spring-expression-5.3.10.jar:5.3.10]
	at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:91) ~[spring-expression-5.3.10.jar:5.3.10]
	at org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:61) ~[spring-expression-5.3.10.jar:5.3.10]
	at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:91) ~[spring-expression-5.3.10.jar:5.3.10]
	at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:112) ~[spring-expression-5.3.10.jar:5.3.10]
	at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:337) ~[spring-expression-5.3.10.jar:5.3.10]
	at org.thymeleaf.spring5.expression.SPELVariableExpressionEvaluator.evaluate(SPELVariableExpressionEvaluator.java:265) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
	at org.thymeleaf.standard.expression.VariableExpression.executeVariableExpression(VariableExpression.java:166) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
	at org.thymeleaf.standard.expression.SimpleExpression.executeSimple(SimpleExpression.java:66) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
	at org.thymeleaf.standard.expression.Expression.execute(Expression.java:109) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
	at org.thymeleaf.standard.expression.Expression.execute(Expression.java:138) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
	at org.thymeleaf.standard.processor.AbstractStandardExpressionAttributeTagProcessor.doProcess(AbstractStandardExpressionAttributeTagProcessor.java:144) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
	at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]

該当のソースコード

html
1      <form th:action="@{./setting_page}" th:method="put" id="update">
2        <div id="main" class="container">
3          <ul class="image_list">
4            <li th:each="lstWorks : ${lstWorksEntity}">
5              <div class="image_box">
6                <img th:src="'data:image/png;Base64,'+${lstWorks.stringImg}" class="thumbnail" alt="img" />
7                <input class="disabled_checkbox" type="checkbox" name="checks" th:id="${lstWorks.id}"
8                th:value="${lstWorks.id}" th:checked="${settingEntity.checks.contains(lstWorks.id)}" />
9                <label th:for="${lstWorks.id}" class="checkbox"></label>
10              </div>
11            </li>
12          </ul>
13          <input type="submit" form="update" id="regist" value="登録">

Java
1	@GetMapping
2	public String setting(Model model) {
3		List<WorksEntity> lstWorksEntity = worksService.worksFindAll();
4		model.addAttribute("lstWorksEntity", lstWorksEntity);
5		model.addAttribute("checks",  new SettingEntity());
6		return "setting";
7	}
8
9	@PutMapping
10	public String displayWorks(Model model,
11								List<WorksEntity> lstWorksEntity, SettingEntity settingEntity)
12								throws IOException {
13
14		List<String> checks = settingEntity.getChecks();
15		worksService.worksUpdate(lstWorksEntity, checks);
16		return "redirect:/MyPortfolio/setting_page";
17	}
18
19

Java
1@Getter @Setter
2public class SettingEntity {
3	private List<String> checks = new ArrayList<>();
4}

試してみたこと

newしないパターンも試しましたが同じエラーでした。

Java
1	@GetMapping
2	public String setting(Model model) {
3		List<WorksEntity> lstWorksEntity = worksService.worksFindAll();
4		model.addAttribute("lstWorksEntity", lstWorksEntity);
5		return "setting";
6	}
7
8	@PutMapping
9	public String displayWorks(List<WorksEntity> lstWorksEntity, SettingEntity settingEntity, Model model)
10								throws IOException {
11		List<String> checks = settingEntity.getChecks();
12		model.addAttribute("checks",  checks);
13		worksService.worksUpdate(lstWorksEntity, checks);
14		return "redirect:/MyPortfolio/setting_page";
15	}