SPRING NamedParameterJdbcTemplate return data after i stop the database service

Question

I'm facing an issue when using NamedParameterJdbcTemplate in my Spring apps to query data from Oracle db.

from insomnia/postman i send parameter with body "IDBILL":"9999" and i received the data billing, but when i tried negative scenario ( Oracle service stoped ) , the apps still return data

i've tried another id billing 8888 and return exception because oracle db stoped as i expected, but after that i've tried to previous id billing 9999 and it return the data

why it return the data even though the database services stoped ? need some advice to solving this problem...thank u ...

here is my function to run the sql :

public JsonObject runServicesNPJT(String psQUERY,ConcurrentHashMap<String, String> chmParam )  
{
    JsonObject oReturn = new JsonObject();
    String json ="";
    namedParameterJT = new NamedParameterJdbcTemplate(ds);
    
    try {
        //SqlParameterSource paramSQL = new MapSqlParameterSource().addValue("tahun", "2021");
        SqlParameterSource paramSQL = new MapSqlParameterSource();
        MapSqlParameterSource msps  = new MapSqlParameterSource();
        for (Entry<String, String> entry : chmParam.entrySet()) {
            msps.addValue(entry.getKey(), entry.getValue());        
        }
        
        paramSQL = new MapSqlParameterSource().addValues(chmParam);
        Map<String, Object>  rs = namedParameterJT.queryForMap(psQUERY, paramSQL);
        json = gson.toJson(rs);
        
    } catch (Exception e) {
        // TODO: handle exception
        if(e.toString().contains("IO"))
        {
            return response.sendResponse(ResponseCode.TIMEOUT, ResponseCode.TIMEOUT.description);
        }else {
            
        }
    }
    JsonElement jeReturn = JsonParser.parseString(json);
    return jeReturn.getAsJsonObject();
    
}

this application.properties

spring.application.name=API-MultiBiller Service Engine
spring.application.version=1.0.0-1



#--YA-- db 
spring.datasource.url=jdbc:oracle:thin:@localhost:9981:xe
spring.datasource.username=MSDATA
spring.datasource.password=MSDATA
spring.datasource.driver-class-oracle.jdbc.driver.OracleDriver
spring.cache.type=none

#spring.datasource.tomcat.validation-query=SELECT 1
#spring.datasource.tomcat.validation-query-timeout=5000
#spring.datasource.tomcat.test-on-borrow=true
#spring.datasource.tomcat.test-on-connect=true

# HikariCP settings
# spring.datasource.hikari.*
spring.datasource.hikari.connection-timeout=5000
#spring.datasource.hikari.maximum-pool-size=5

this my pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-hateoas</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    
    <!-- YA untuk Oracle JDBC driver support oraclexe 11g-->
    <!-- https://mvnrepository.com/artifact/com.oracle.database.jdbc/ojdbc10 -->
    <dependency>
        <groupId>com.oracle.database.jdbc</groupId>
        <artifactId>ojdbc8</artifactId>
        <version>12.2.0.1</version>
    </dependency>
    
    <!-- https://mvnrepository.com/artifact/org.json/json -->
    <dependency>
        <groupId>org.json</groupId>
        <artifactId>json</artifactId>
        <version>20211205</version>
    </dependency>
            

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        </dependency>
    
    <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
    </dependency>
</dependencies>