java enum object can express the relationship of inheritance easily. the calculator enum object implements the abstract method named ‘calculate()’ as you can see the below code. the each elements in t
targetCompatibility and sourceCompatibility maps to -target release and -source release in javac. Source is basically the source language level and target is the level of the bytecode that is generate
Why Reactive Programming ?Traditional ProgrammingTraditional Programming makes a call to the DB and the code goes into a blocking phase and wait for the result. Once the result is retrieved from the D
if you build the project as a multi-module one, then you would be encoutered this error when you run .jar file. 1[project name].jar에 기본 Manifest 속성이 없습니다 the factor is the sub module can’t find the en
Mac OSFirst of all, let’s check the java version in your local system via the below command. 1> java -version the below command will able to check the list of installed JDK in OSX system. 1> /us
123public interface ExceptionFunction<T, R> { R apply(T t) throws Exception;} 1234567891011public class ExceptionUtil { public static <T, R> Function<T, R> wrap(
@NotNull Null 값을 허용하지 않는다. @NotEmpty Null 값과 “” 값을 허용하지 않는다. @NotBlank Null 값과 “” 값과 “ “ 값을 허용하지 않는다. @Email 입력 값이 이메일 형식이 아니라면 허용하지 않는다. @Min(1) 1자 이상의 값만을 허용한다. @Max(10) 10자 미만의 값만을
Enum objects usually return their value data (no field data) when you serialize it. if you want to change this, you can use @JsonValue, @JsonFormat annotation in Jackson library that is the main part
123ObjectMapper mapper = new ObjectMapper();mapper.registerModule(new JavaTimeModule()); // 추가mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS); // 추가