Downloaded 13 times
![!"" lib
!"" run.sh
#"" src
!"" books
$ !"" api
$ $ !"" entities
$ $ $ #"" Book.java
$ $ #"" service
$ $ #"" BooksService.java
$ #"" impl
$ !"" entities
$ $ #"" BookEntity.java
$ #"" service
$ #"" HibernateBooksService.java
!"" bookstore
$ !"" api
$ $ #"" service
$ $ #"" BookstoreService.java
$ #"" impl
$ #"" service
$ #"" BookstoreServiceImpl.java
!"" log4j2.xml
!"" main
$ #"" Main.java
#"" main.xml
javac -cp [list of JARs in lib]
-d out -sourcepath src $(find src -name '*.java')
cp $(find src -name '*.xml') out
java -cp [list of JARs in lib]:out main.Main](https://image.slidesharecdn.com/migratingtojava9modules-171006052108/85/Migrating-to-java-9-modules-9-320.jpg)
![Step 6 - Illegal deep reflection.
java.lang.reflect.InaccessibleObjectException: Unable to make
protected final java.lang.Class
java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int
,java.security.ProtectionDomain) throws
java.lang.ClassFormatError accessible: module java.base does not
"opens java.lang" to module javassist
java -cp $CLASSPATH
--add-modules java.sql,java.xml.bind
--add-opens java.base/java.lang=javassist
--module-path mods:out
-m bookapp/main.Main](https://image.slidesharecdn.com/migratingtojava9modules-171006052108/85/Migrating-to-java-9-modules-31-320.jpg)
Uploaded byPaul Bakker
Migrating to java 9 modules
The document discusses the migration to Java 9 modules, highlighting the reasons for using modules, the transition from Java 8, and the associated challenges and solutions. It outlines the steps for refactoring existing projects, managing dependencies, and addressing issues with reflection and library compatibility during the migration process. Additionally, it provides examples of module definitions and build configurations necessary for successful implementation.
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Migrating to java 9 modules
- 1. Migrating to Java9 Modules | Paul Bakker
- 2. Why care aboutmodules? lib/nebula-4.0.12.jar:lib/netflix-gradle-lint-8.6.1.jar:lib/gretty-2.0.0.jar:lib/gradle-infamous-plugin-1.28.jar:lib/java-semver-0.9.0.jar:lib/guava-20.0.jar:lib/ nebula-core-4.0.1.jar:lib/commons-lang-2.6.jar:lib/joda-time-2.9.9.jar:lib/kotlin-reflect-1.1.4-3.jar:lib/nebula-common-4.0.12.jar:lib/nebula-repos-4.0.12.jar:lib/ nebula-publish-4.0.12.jar:lib/httpclient-4.5.3.jar:lib/jgrapht-core-0.9.2.jar:lib/build-info-extractor-gradle-4.1.1.jar:lib/ant-jsch-1.9.9.jar:lib/rest-api-client- core-1.9.0.jar:lib/rest-api-client-httpclient-1.9.0.jar:lib/bakery-api-client-1.8.0.jar:lib/odin-2.0.0.jar:lib/artifactory-java-client-services-1.2.2.jar:lib/ kotlin-stdlib-jre8-1.1.4-3.jar:lib/gradle-contacts-plugin-3.0.1.jar:lib/gradle-dependency-lock-plugin-4.9.4.jar:lib/gradle-extra-configurations- plugin-3.2.0.jar:lib/gradle-git-scm-plugin-3.0.1.jar:lib/gradle-info-plugin-3.6.0.jar:lib/gradle-java-cross-compile-plugin-0.9.0.jar:lib/gradle-lint- plugin-8.3.1.jar:lib/gradle-metrics-plugin-6.0.0.jar:lib/gradle-ospackage-plugin-4.4.0.jar:lib/gradle-override-plugin-3.0.2.jar:lib/gradle-resolution-rules- plugin-5.0.2.jar:lib/gradle-scm-plugin-3.0.1.jar:lib/gradle-stash-plugin-4.0.1.jar:lib/nebula-dependency-base-plugin-0.3.0.jar:lib/nebula-dependency- recommender-5.0.0.jar:lib/nebula-grails-plugin-1.0.0.jar:lib/nebula-project-plugin-3.4.0.jar:lib/nebula-release-plugin-6.0.1.jar:lib/gradle-release-1.2.jar:lib/ gradle-cobertura-plugin-2.5.0.jar:lib/gretty-core-2.0.0.jar:lib/spring-boot-loader-tools-1.5.4.RELEASE.jar:lib/jetty-util-8.1.8.v20121106.jar:lib/httpclient- cache-4.5.2.jar:lib/kotlin-stdlib-1.1.4-3.jar:lib/metatron-decrypt-1.108.0.jar:lib/nebula-publishing-plugin-5.1.3.jar:lib/httpcore-4.4.6.jar:lib/commons- logging-1.2.jar:lib/commons-codec-1.9.jar:lib/ivy-2.2.0.jar:lib/build-info-extractor-2.5.5.jar:lib/ant-1.9.9.jar:lib/mail-1.4.4.jar:lib/frigga-0.13.jar:lib/ nekohtml-1.9.17.jar:lib/artifactory-java-client-api-1.2.2.jar:lib/groovy-xml-2.3.2.jar:lib/jcl-over-slf4j-1.7.2.jar:lib/kotlin-stdlib-jre7-1.1.4-3.jar:lib/ svnkit-1.8.12.jar:lib/asm-5.2.jar:lib/gpars-1.2.1.jar:lib/junit-4.12.jar:lib/jackson-datatype-joda-2.3.2.jar:lib/logstash-logback-encoder-4.5.1.jar:lib/ jest-0.1.7.jar:lib/fluent-hc-4.5.1.jar:lib/redline-1.2.5.jar:lib/jdeb-1.4.jar:lib/gradle-docker-plugin-3.0.1.jar:lib/commons-beanutils-core-1.8.3.jar:lib/jackson- module-kotlin-2.7.5.jar:lib/maven-model-builder-3.5.0.jar:lib/grails-launcher-1.1.jar:lib/groovy-2.4.11.jar:lib/commons-cli-1.2.jar:lib/commons- configuration-1.10.jar:lib/org.apache.servicemix.bundles.bcprov-jdk16-1.46_3.jar:lib/spring-boot-devtools-1.3.3.RELEASE.jar:lib/spring-core-4.3.9.RELEASE.jar:lib/ annotations-13.0.jar:lib/gson-2.8.0.jar:lib/protobuf-java-util-3.2.0.jar:lib/protobuf-java-3.2.0.jar:lib/grpc-core-1.3.0.jar:lib/javax.inject-1.jar:lib/metatron- common-1.108.0.jar:lib/metatron-ipc-common-1.108.0.jar:lib/build-info-client-2.5.5.jar:lib/xstream-1.3.1.jar:lib/ant-launcher-1.9.9.jar:lib/multiverse- core-0.7.0.jar:lib/jsr166y-1.7.0.jar:lib/hamcrest-core-1.3.jar:lib/logback-core-1.1.3.jar:lib/jest-common-0.1.7.jar:lib/httpcore-nio-4.4.1.jar:lib/ httpasyncclient-4.1.jar:lib/plexus-utils-3.0.24.jar:lib/plexus-interpolation-1.24.jar:lib/plexus-component-annotations-1.7.1.jar:lib/maven-model-3.5.0.jar:lib/ maven-artifact-3.5.0.jar:lib/maven-builder-support-3.5.0.jar:lib/spring-boot-1.3.3.RELEASE.jar:lib/spring-boot-autoconfigure-1.3.3.RELEASE.jar:lib/ error_prone_annotations-2.0.19.jar:lib/jsr305-3.0.0.jar:lib/grpc-context-1.3.0.jar:lib/instrumentation-api-0.3.0.jar:lib/grpc-protobuf-1.3.0.jar:lib/grpc- stub-1.3.0.jar:lib/jackson-mapper-asl-1.9.12.jar:lib/build-info-api-2.5.5.jar:lib/xpp3_min-1.1.4c.jar:lib/spring-context-4.2.5.RELEASE.jar:lib/grpc-google-common- protos-0.1.6.jar:lib/grpc-protobuf-lite-1.3.0.jar:lib/jackson-core-asl-1.9.12.jar:lib/spring-aop-4.2.5.RELEASE.jar:lib/spring-beans-4.2.5.RELEASE.jar:lib/spring- expression-4.2.5.RELEASE.jar:lib/aopalliance-1.0.jar:lib/http-builder-0.7.1.jar:lib/json-lib-2.3-jdk15.jar:lib/xml-resolver-1.2.jar:lib/commons- beanutils-1.8.0.jar:lib/commons-collections-3.2.1.jar:lib/ezmorph-1.0.6.jar:lib/slf4j-api-1.7.25.jar:lib/commons-io-2.5.jar:lib/jackson-annotations-2.7.5.jar:lib/ jackson-databind-2.7.5.jar:lib/nebula-gradle-interop-0.5.0.jar:lib/org.eclipse.jgit.ui-4.6.1.201703071140-r.jar:lib/jsch.agentproxy.jsch-0.0.9.jar:lib/ jsch.agentproxy.pageant-0.0.9.jar:lib/jsch.agentproxy.sshagent-0.0.9.jar:lib/jsch.agentproxy.usocket-jna-0.0.9.jar:lib/jsch.agentproxy.usocket-nc-0.0.9.jar:lib/ jsch.agentproxy.core-0.0.9.jar:lib/jna-4.1.0.jar:lib/jna-platform-4.1.0.jar:lib/p4java-2015.2.1365273.jar:lib/jzlib-1.1.2.jar:lib/jsch.agentproxy.svnkit-trilead- ssh2-0.0.7.jar:lib/trilead-ssh2-1.0.0-build220.jar:lib/jsch.agentproxy.connector-factory-0.0.7.jar:lib/sequence-library-1.0.3.jar:lib/sqljet-1.1.10.jar:lib/antlr- runtime-3.4.jar:lib/commons-lang3-3.5.jar:lib/gradle-git-1.7.2.jar:lib/groovy-json-2.4.11.jar:lib/commons-compress-1.8.jar:lib/bcpg-jdk15on-1.51.jar:lib/bcprov- jdk15on-1.51.jar:lib/xercesImpl-2.9.1.jar:lib/jackson-core-2.7.5.jar:lib/org.eclipse.jgit-4.6.1.201703071140-r.jar:lib/JavaEWAH-1.1.6.jar:lib/jsch-0.1.54.jar:lib/ grgit-1.9.3.jar:lib/xz-1.5.jar
- 3. module easytext.cli { requireseasytext.analysis; } module easytext.analysis { exports analysis.api; opens impl; } easytext.cli easytext.analysis other analysis.api impl reflection only! Module primer.
- 4. module easytext.cli { requireseasytext.analysis; } module easytext.analysis { exports analysis.api; opens impl; } easytext.cli easytext.analysis other analysis.api impl reflection only! Module primer. Modules define dependencies explicitly
- 5. module easytext.cli { requireseasytext.analysis; } module easytext.analysis { exports analysis.api; opens impl; } easytext.cli easytext.analysis other analysis.api impl reflection only! Module primer. Packages are encapsulated by default
- 6. module easytext.cli { requireseasytext.analysis; } module easytext.analysis { exports analysis.api; opens impl; } easytext.cli easytext.analysis other analysis.api impl reflection only! Module primer. Packages can be “opened” for deep reflection at run-time
- 7. Migrating to Java9. Java 8 Java 9 java -cp … -jar MyApp.jar java -cp … -jar MyApp.jar
- 8. Our journey tomodules. Running on Java 9 Using existing libraries Allowing reflection Spring / Hibernate case study Refactoring to increase modularity Migrating builds
- 9. !"" lib !"" run.sh #""src !"" books $ !"" api $ $ !"" entities $ $ $ #"" Book.java $ $ #"" service $ $ #"" BooksService.java $ #"" impl $ !"" entities $ $ #"" BookEntity.java $ #"" service $ #"" HibernateBooksService.java !"" bookstore $ !"" api $ $ #"" service $ $ #"" BookstoreService.java $ #"" impl $ #"" service $ #"" BookstoreServiceImpl.java !"" log4j2.xml !"" main $ #"" Main.java #"" main.xml javac -cp [list of JARs in lib] -d out -sourcepath src $(find src -name '*.java') cp $(find src -name '*.xml') out java -cp [list of JARs in lib]:out main.Main
- 10. Missing platform libraries. importjavax.xml.bind.DatatypeConverter; public class Main { public static void main(String... args) { DatatypeConverter.parseBase64Binary("SGVsbG8gd29ybGQh"); } } java.lang.ClassNotFoundException: javax.xml.bind.JAXBException
- 11. The platform modulegraph.
- 12.
- 13. Resolving JAXB. java --add-modulesjava.xml.bind …
- 14. Illegal deep reflection. WARNING:An illegal reflective access operation has occurred WARNING: Illegal reflective access by javassist.util.proxy.SecurityActions … WARNING: Please consider reporting this to the maintainers of javassist.util.proxy.SecurityActions WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release
- 15. Type Compile timeReflection on public Deep reflection Exports ✓ ✓ ✘ Open ✘ ✓ ✓ Exports + Open ✓ ✓ ✓
- 16. Fixing illegal deepreflection. Use a library that doesn’t do this! do you really need deep reflection on JDK types!? Use command line flags to open packages java --add-opens java.base/java.lang=ALL-UNNAMED Main
- 17.
- 18. But we’re stillon the classpath!
- 19. Let’s migrate ourcode to modules But how do we deal with libraries?
- 20. package demo; import com.fasterxml.jackson.databind.ObjectMapper; publicclass Main { public static void main(String... args) throws Exception { Book modularityBook = new Book("Java 9 Modularity", "Modularize all the things!"); ObjectMapper mapper = new ObjectMapper(); String json = mapper.writeValueAsString(modularityBook); System.out.println(json); } } module books { }
- 21. Automatic modules -A non- modular JAR on the module path Exports all packages Requires all resolved modules Can read the class path (the unnamed module)
- 22. CP=lib/jackson-annotations-2.8.8.jar: CP+=lib/jackson-core-2.8.8.jar javac -cp $CP--module-path mods -d out --module-source-path src -m books module books { requires jackson.databind; }
- 23.
- 24. Sample app aftermigration.
- 25. Step 1 -Project structure. !"" lib !"" mods !"" run.sh #"" src #"" bookapp !"" books $ !"" api $ $ !"" entities $ $ $ #"" Book.java $ $ #"" service $ $ #"" BooksService.java $ #"" impl $ !"" entities $ $ #"" BookEntity.java $ #"" service $ #"" HibernateBooksService.java !"" bookstore $ !"" api $ $ #"" service $ $ #"" BookstoreService.java $ #"" impl $ #"" service $ #"" BookstoreServiceImpl.java !"" log4j2.xml !"" main $ #"" Main.java !"" main.xml #"" module-info.java “mods” dir for automatic modules Single module dir (for now) Add module-info.java javac -cp $CLASSPATH --module-path mods -d out --module-source-path src -m bookapp
- 26. Step 2 -Add requires. BookstoreServiceImpl.java:7: error: package org.springframework.stereotype is not visible import org.springframework.stereotype.Component; Compilation error Our module needs explicit dependencies!
- 27. Step 3 -Add missing compile time platform modules. HibernateBooksService.java:19: error: cannot access Referenceable return sessionFactory.getCurrentSession().get(BookEntity.class, id); ^ class file for javax.naming.Referenceable not found Compilation error Hibernate should declare requires transitive java.naming
- 28. Running. java -cp $CLASSPATH --module-pathmods:out -m bookapp/main.Main
- 29. Step 4 -Add missing platform modules. java.lang.ClassNotFoundException: java.sql.SQLException java -cp $CLASSPATH --add-modules java.sql,java.xml.bind --module-path mods:out -m bookapp/main.Main
- 30. Step 5 -Open packages for reflection. java.lang.IllegalAccessException: class org.springframework.beans.BeanUtils cannot access class books.impl.service.HibernateBooksService (in module bookapp) because module bookapp does not export books.impl.service to unnamed module @5c45d770 opens books.impl.entities; opens books.impl.service; opens bookstore.impl.service;
- 31. Step 6 -Illegal deep reflection. java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int ,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to module javassist java -cp $CLASSPATH --add-modules java.sql,java.xml.bind --add-opens java.base/java.lang=javassist --module-path mods:out -m bookapp/main.Main
- 32.
- 33.
- 34.
- 35. main books.api books.impl bookstore.api requires requires requires Module System usesprovides bookstore.impl provides
- 36. Build tools. <artifactId>bookstore</artifactId> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>9</source> <target>9</target> </configuration> </plugin> </plugins> </build> <dependencies> <dependency> <groupId>javamodularity</groupId> <artifactId>books</artifactId> <version>1.0-SNAPSHOT</version> </dependency> </dependencies> modulebookstore { requires books; exports bookstore.service.api; uses books.api.service.BooksService; provides bookstore.service.api.BookstoreService with bookstore.service.impl.BookstoreServiceImpl; }
- 37.