feat(cf-env): add Spring Boot 4.x support and improve docs

- Add detection tests for SB 4.0 and 4.1 (BOOT-INF/lib, lib/, WEB-INF/lib, MANIFEST.MF)
- Update detection criterion to cover both SB 3.x and 4.x
- Add version mapping table: SB 3.x → cfenv 3.x, SB 4.x → cfenv 4.x
- Clarify cloud profile is activated by the library at runtime, not the buildpack
- Add JBP_CONFIG_JAVA_CF_ENV configuration section with enable/disable examples
- Document when to disable (manual VCAP_SERVICES handling, unwanted cloud profile, conflicts)

Author: stokpop

docs/framework-java-cfenv.md

@@ -1,19 +1,51 @@
 # Java CfEnv Framework
-The Java CfEnv Framework provides the `java-cfenv` library for Spring Boot 3+ applications. This library sets various Spring Boot properties by parsing CloudFoundry variables such as `VCAP_SERVICES`, allowing Spring Boot's autoconfiguration to kick in. 
+The Java CfEnv Framework provides the `java-cfenv` library for Spring Boot 3.x and 4.x applications. This library sets various Spring Boot properties by parsing CloudFoundry variables such as `VCAP_SERVICES`, allowing Spring Boot's autoconfiguration to kick in.
 
-This is the recommended replacement for Spring AutoReconfiguration library which is deprecated. See the `java-cfenv` <a href="https://github.com/pivotal-cf/java-cfenv">repostitory</a> for more detail.
+This is the recommended replacement for Spring AutoReconfiguration library which is deprecated. See the `java-cfenv` <a href="https://github.com/pivotal-cf/java-cfenv">repository</a> for more detail.
 
-It also sets the 'cloud' profile for Spring Boot applications, as the Spring AutoReconfiguration framework did.
+The included `java-cfenv` library activates the `cloud` Spring profile at runtime when `VCAP_SERVICES` is present, as the Spring AutoReconfiguration framework did. The buildpack itself does not set any Spring profile.
+
+The buildpack selects the appropriate `java-cfenv` version based on the detected Spring Boot major version:
+
+| Spring Boot | java-cfenv |
+|-------------|------------|
+| 3.x | 3.x (latest) |
+| 4.x | 4.x (latest) |
 
 <table>
   <tr>
     <td><strong>Detection Criterion</strong></td>
-    <td>Existence of a `Spring-Boot-Version: 3.*` manifest entry</td>
-    <td>No existing `java-cfenv` library found</td>
+    <td>Existence of a <tt>spring-boot-3.*.jar</tt> or <tt>spring-boot-4.*.jar</tt> in <tt>BOOT-INF/lib</tt>, <tt>WEB-INF/lib</tt>, or <tt>lib/</tt>; or a <tt>Spring-Boot-Version: 3.*</tt> / <tt>Spring-Boot-Version: 4.*</tt> entry in <tt>META-INF/MANIFEST.MF</tt></td>
+    <td>No existing <tt>java-cfenv</tt> library found in the application</td>
   </tr>
   <tr>
     <td><strong>Tags</strong></td>
     <td><tt>java-cf-env=&lt;version&gt;</tt></td>
   </tr>
 </table>
 Tags are printed to standard output by the buildpack detect script
+
+## Configuration
+
+The framework can be disabled via the `JBP_CONFIG_JAVA_CF_ENV` environment variable:
+
+```bash
+cf set-env <app> JBP_CONFIG_JAVA_CF_ENV '{enabled: false}'
+```
+
+To re-enable, either set it back to `{enabled: true}` or remove the variable entirely:
+
+```bash
+cf unset-env <app> JBP_CONFIG_JAVA_CF_ENV
+```
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `JBP_CONFIG_JAVA_CF_ENV` | `{enabled: true}` | Enable or disable the framework |
+
+Note: if `java-cfenv*.jar` is already present in the application, the buildpack skips injection automatically — no need to disable explicitly for that case.
+
+Disable when:
+- The application handles `VCAP_SERVICES` manually with custom binding logic
+- The automatic `cloud` profile activation is unwanted
+- Another service binding library conflicts with `java-cfenv`

src/java/frameworks/java_cf_env_test.go

@@ -68,10 +68,23 @@ var _ = Describe("Java CF Env", func() {
 			})
 		})
 
-		Context("with Spring Boot 3.x JAR in lib/", func() {
+		Context("with Spring Boot 4.1.x JAR in BOOT-INF/lib", func() {
+			BeforeEach(func() {
+				Expect(os.MkdirAll(filepath.Join(buildDir, "BOOT-INF", "lib"), 0755)).To(Succeed())
+				Expect(os.WriteFile(filepath.Join(buildDir, "BOOT-INF", "lib", "spring-boot-4.1.0.jar"), []byte("fake"), 0644)).To(Succeed())
+			})
+
+			It("returns 'Java CF Env'", func() {
+				name, err := fw.Detect()
+				Expect(err).NotTo(HaveOccurred())
+				Expect(name).To(Equal("Java CF Env"))
+			})
+		})
+
+		Context("with Spring Boot 4.1.x JAR in lib/", func() {
 			BeforeEach(func() {
 				Expect(os.MkdirAll(filepath.Join(buildDir, "lib"), 0755)).To(Succeed())
-				Expect(os.WriteFile(filepath.Join(buildDir, "lib", "spring-boot-3.1.5.jar"), []byte("fake"), 0644)).To(Succeed())
+				Expect(os.WriteFile(filepath.Join(buildDir, "lib", "spring-boot-4.1.0.jar"), []byte("fake"), 0644)).To(Succeed())
 			})
 
 			It("returns 'Java CF Env'", func() {
@@ -81,10 +94,10 @@ var _ = Describe("Java CF Env", func() {
 			})
 		})
 
-		Context("with Spring Boot 3.x JAR in WEB-INF/lib", func() {
+		Context("with Spring Boot 4.1.x JAR in WEB-INF/lib", func() {
 			BeforeEach(func() {
 				Expect(os.MkdirAll(filepath.Join(buildDir, "WEB-INF", "lib"), 0755)).To(Succeed())
-				Expect(os.WriteFile(filepath.Join(buildDir, "WEB-INF", "lib", "spring-boot-3.0.0.jar"), []byte("fake"), 0644)).To(Succeed())
+				Expect(os.WriteFile(filepath.Join(buildDir, "WEB-INF", "lib", "spring-boot-4.1.0.jar"), []byte("fake"), 0644)).To(Succeed())
 			})
 
 			It("returns 'Java CF Env'", func() {
@@ -94,12 +107,12 @@ var _ = Describe("Java CF Env", func() {
 			})
 		})
 
-		Context("with Spring-Boot-Version: 3.x in META-INF/MANIFEST.MF", func() {
+		Context("with Spring-Boot-Version: 4.1.x in META-INF/MANIFEST.MF", func() {
 			BeforeEach(func() {
 				Expect(os.MkdirAll(filepath.Join(buildDir, "META-INF"), 0755)).To(Succeed())
 				Expect(os.WriteFile(
 					filepath.Join(buildDir, "META-INF", "MANIFEST.MF"),
-					[]byte("Manifest-Version: 1.0\nSpring-Boot-Version: 3.2.0\nMain-Class: org.springframework.boot.loader.JarLauncher\n"),
+					[]byte("Manifest-Version: 1.0\nSpring-Boot-Version: 4.1.0\nMain-Class: org.springframework.boot.loader.JarLauncher\n"),
 					0644,
 				)).To(Succeed())
 			})