Add boot4-migration module: one Boot 3.5.16 service migrated to 4.1.2, with the real compile, start-up, silent and test failures captured at each step

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b4VQVEJWetTT1dYzyJ
2026-10-29 05:57:26 +00:00
parent fd0cf9b527
commit 85074ed51a
45 changed files with 1021 additions and 0 deletions
@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- THE "BEFORE" APP: a Spring Boot 3.5.16 service written the way most 3.x services are.
+     It is NOT part of any build in this repository; scripts/run-all.sh copies it to a scratch
+     directory and builds it there, first as-is and then with the parent bumped to 4.1.2. -->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.springframework.boot</groupId>
+    <artifactId>spring-boot-starter-parent</artifactId>
+    <version>3.5.16</version>
+    <relativePath/>
+  </parent>
+  <groupId>com.ankurm</groupId>
+  <artifactId>migration-demo</artifactId>
+  <version>1.0.0</version>
+  <properties>
+    <java.version>25</java.version>
+  </properties>
+  <dependencies>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-security</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-aop</artifactId></dependency>
+    <dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency>
+    <!-- Boot 3: Flyway needs only the library, Boot's auto-configuration was in the big autoconfigure jar -->
+    <dependency><groupId>org.flywaydb</groupId><artifactId>flyway-core</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
+    <dependency><groupId>org.springframework.security</groupId><artifactId>spring-security-test</artifactId><scope>test</scope></dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin>
+    </plugins>
+  </build>
+</project>
@@ -0,0 +1,11 @@
+package com.ankurm.migration;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class DemoApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(DemoApplication.class, args);
+    }
+}
@@ -0,0 +1,18 @@
+package com.ankurm.migration;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestClient;
+
+/** Takes the auto-configured RestClient.Builder. RestClient itself lives in spring-web, so this always compiles. */
+@Component
+public class Gateway {
+    private final RestClient client;
+
+    public Gateway(RestClient.Builder builder) {
+        this.client = builder.baseUrl("http://localhost:9").build();
+    }
+
+    public String describe() {
+        return client.getClass().getSimpleName();
+    }
+}
@@ -0,0 +1,6 @@
+package com.ankurm.migration;
+
+import java.time.Instant;
+
+public record Greeting(long id, String title, Instant createdAt, String author) {
+}
@@ -0,0 +1,62 @@
+package com.ankurm.migration;
+
+import java.time.Instant;
+import java.util.Map;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class GreetingController {
+
+    private static final Logger log = LoggerFactory.getLogger(GreetingController.class);
+
+    private final GreetingService service;
+    private final JdbcTemplate jdbc;
+    private final Gateway gateway;
+
+    public GreetingController(GreetingService service, JdbcTemplate jdbc, Gateway gateway) {
+        this.service = service;
+        this.jdbc = jdbc;
+        this.gateway = gateway;
+    }
+
+    @GetMapping("/greetings/{id}")
+    public Greeting greeting(@PathVariable long id) {
+        log.info("served greeting {} ........................................", id);
+        return new Greeting(id, service.title(id), Instant.parse("2026-01-02T03:04:05Z"), "ankur");
+    }
+
+    /** Serialised by Jackson's default record handling (no custom serializer). */
+    @GetMapping("/summary")
+    public Summary summary() {
+        Summary s = new Summary();
+        s.setId(1);
+        s.setTitle("Hello");
+        s.setCreatedAt(Instant.parse("2026-01-02T03:04:05Z"));
+        s.setAuthor("ankur");
+        return s;
+    }
+
+    /** Reads the table that the Flyway migration V1 creates. */
+    @GetMapping("/greetings/count")
+    public Map<String, Object> count() {
+        Integer n = jdbc.queryForObject("select count(*) from greeting", Integer.class);
+        return Map.of("rows", n);
+    }
+
+    /** How many times the @Aspect has intercepted GreetingService. */
+    @GetMapping("/aspect")
+    public Map<String, Object> aspect() {
+        return Map.of("interceptions", TimingAspect.COUNT.get());
+    }
+
+    @GetMapping("/gateway")
+    public Map<String, Object> gateway() {
+        return Map.of("client", gateway.describe());
+    }
+}
@@ -0,0 +1,10 @@
+package com.ankurm.migration;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class GreetingService {
+    public String title(long id) {
+        return "Hello #" + id;
+    }
+}
@@ -0,0 +1,22 @@
+package com.ankurm.migration;
+
+import java.io.IOException;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import org.springframework.boot.jackson.JsonComponent;
+
+/** Boot 3 idiom: a Jackson 2 serializer registered through Boot's @JsonComponent. */
+@JsonComponent
+public class JsonConfig extends JsonSerializer<Greeting> {
+    @Override
+    public void serialize(Greeting g, JsonGenerator gen, SerializerProvider sp) throws IOException {
+        gen.writeStartObject();
+        gen.writeNumberField("id", g.id());
+        gen.writeStringField("title", g.title());
+        gen.writeStringField("createdAt", g.createdAt().toString());
+        gen.writeStringField("author", g.author());
+        gen.writeEndObject();
+    }
+}
@@ -0,0 +1,23 @@
+package com.ankurm.migration;
+
+import org.springframework.boot.autoconfigure.security.SecurityProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.Order;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.web.SecurityFilterChain;
+
+@Configuration
+public class SecurityConfig {
+
+    @Bean
+    @Order(SecurityProperties.BASIC_AUTH_ORDER)
+    SecurityFilterChain chain(HttpSecurity http) throws Exception {
+        http.authorizeHttpRequests()
+                .requestMatchers("/actuator/health/**", "/greetings/**", "/aspect", "/gateway").permitAll()
+                .anyRequest().authenticated()
+                .and()
+            .httpBasic();
+        return http.build();
+    }
+}
@@ -0,0 +1,24 @@
+package com.ankurm.migration;
+
+import java.time.Instant;
+
+/**
+ * A plain bean (not a record) whose properties are deliberately NOT in alphabetical order.
+ * Jackson 2 wrote them in declaration order; Jackson 3 sorts bean properties alphabetically by default.
+ * (Records are unaffected: creator parameters are always written first, in constructor order.)
+ */
+public class Summary {
+    private long id;
+    private String title;
+    private Instant createdAt;
+    private String author;
+
+    public long getId() { return id; }
+    public void setId(long id) { this.id = id; }
+    public String getTitle() { return title; }
+    public void setTitle(String title) { this.title = title; }
+    public Instant getCreatedAt() { return createdAt; }
+    public void setCreatedAt(Instant createdAt) { this.createdAt = createdAt; }
+    public String getAuthor() { return author; }
+    public void setAuthor(String author) { this.author = author; }
+}
@@ -0,0 +1,21 @@
+package com.ankurm.migration;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.aspectj.lang.annotation.Around;
+import org.aspectj.lang.annotation.Aspect;
+import org.springframework.stereotype.Component;
+
+/** Needs AspectJ weaving support on the classpath: spring-boot-starter-aop in Boot 3. */
+@Aspect
+@Component
+public class TimingAspect {
+    static final AtomicInteger COUNT = new AtomicInteger();
+
+    @Around("execution(* com.ankurm.migration.GreetingService.*(..))")
+    public Object count(ProceedingJoinPoint pjp) throws Throwable {
+        COUNT.incrementAndGet();
+        return pjp.proceed();
+    }
+}
@@ -0,0 +1,7 @@
+spring.datasource.url=jdbc:h2:mem:demo;DB_CLOSE_DELAY=-1
+management.endpoints.web.exposure.include=health,metrics
+management.endpoint.health.show-details=always
+# Boot 3 logging properties that were deprecated for years (replaced by logging.logback.rollingpolicy.*)
+logging.file.name=${LOG_DIR:target/logs}/app.log
+logging.file.max-size=2KB
+logging.file.max-history=50
@@ -0,0 +1,2 @@
+create table greeting (id bigint primary key, title varchar(100) not null);
+insert into greeting values (1, 'first'), (2, 'second'), (3, 'third');
@@ -0,0 +1,24 @@
+package com.ankurm.migration;
+
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.httpBasic;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.web.servlet.MockMvc;
+
+/** Prints the status of a Basic-authenticated POST without a CSRF token (to compare 3.5 with 4.1). */
+@SpringBootTest(properties = "spring.security.user.password=pw")
+@AutoConfigureMockMvc
+class CsrfProbeTest {
+
+    @Autowired MockMvc mvc;
+
+    @Test
+    void postWithoutCsrfToken() throws Exception {
+        int status = mvc.perform(post("/anything").with(httpBasic("user", "pw"))).andReturn().getResponse().getStatus();
+        System.out.println("CSRFPROBE status=" + status);
+    }
+}
@@ -0,0 +1,27 @@
+package com.ankurm.migration;
+
+import static org.mockito.BDDMockito.given;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.test.web.servlet.MockMvc;
+
+@SpringBootTest
+@AutoConfigureMockMvc
+class GreetingControllerTest {
+
+    @Autowired MockMvc mvc;
+    @MockBean GreetingService service;
+
+    @Test
+    void greetingUsesService() throws Exception {
+        given(service.title(7)).willReturn("mocked");
+        mvc.perform(get("/greetings/7")).andExpect(status().isOk()).andExpect(jsonPath("$.title").value("mocked"));
+    }
+}
@@ -0,0 +1,22 @@
+package com.ankurm.migration;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.springframework.boot.test.context.SpringBootTest;
+
+/**
+ * A plain Mockito @Mock field inside a @SpringBootTest, with no MockitoExtension.
+ * Boot 3 initialised it through MockitoTestExecutionListener; Boot 4 removed that listener.
+ */
+@SpringBootTest
+class MockFieldTest {
+
+    @Mock Runnable task;
+
+    @Test
+    void mockFieldIsInitialised() {
+        assertNotNull(task, "@Mock field was never initialised");
+    }
+}