출처 : <a href="https://stackoverflow.com/questions/37968696/how-to-run-code-after-constructor-in-a-lombok-builder">https://stackoverflow.com/questions/37968696/how-to-run-code-after-constructor-in-a-lombok-builder</a>&nbsp;&nbsp;빌더패턴 사용하고나서 초기값을 줘야할 때&nbsp;<h2>after build function</h2><pre style="background-color:#2b2b2b;color:#a9b7c6;font-family:'D2Coding',monospace;font-size:11.3pt;">import lombok.Builder; import lombok.Singular; import lombok.ToString; import java.util.List; import java.util.Optional; @Builder(buildMethodName = "buildInternal") @ToString public class Foo { public String val1; public int val2; @Singular public List&lt;String&gt; listValues; public void init() { // do some checks with the values. } /** * Add some functionality to the generated builder class */ public static class FooBuilder { public Optional&lt;Foo&gt; buildOptional() { return Optional.of(this.build()); } public Foo build() { Foo foo = this.buildInternal(); foo.init(); return foo; } } } &nbsp;</pre>&nbsp;<h2>테스트 방법</h2><pre style="background-color:#2b2b2b;color:#a9b7c6;font-family:'D2Coding',monospace;font-size:11.3pt;">public static void main(String[] args) { Foo foo = Foo.builder().val1("String").val2(14) .listValue("1").listValue("2").build(); System.out.println(foo); Optional&lt;Foo&gt; fooOpt = Foo.builder().val1("String").val2(14) .listValue("1").listValue("2").buildOptional(); System.out.println(fooOpt); }</pre>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

lombok의 @Builder annotation을 사용할 때, Build 함수를 실행 후 실행할 함수를 정의하는 방법/초기값 주는 방법 after/post build function