Migrating to Java 9 Modules. Paul Bakker

Transcription

1 Migrating to Java 9 Modules Paul Bakker

2 Why care about modules? lib/nebula jar:lib/netflix-gradle-lint jar:lib/gretty jar:lib/gradle-infamous-plugin-1.28.jar:lib/java-semver jar:lib/guava-20.0.jar:lib/ nebula-core jar:lib/commons-lang-2.6.jar:lib/joda-time jar:lib/kotlin-reflect jar:lib/nebula-common jar:lib/nebula-repos jar:lib/ nebula-publish jar:lib/httpclient jar:lib/jgrapht-core jar:lib/build-info-extractor-gradle jar:lib/ant-jsch jar:lib/rest-api-clientcore jar:lib/rest-api-client-httpclient jar:lib/bakery-api-client jar:lib/odin jar:lib/artifactory-java-client-services jar:lib/ kotlin-stdlib-jre jar:lib/gradle-contacts-plugin jar:lib/gradle-dependency-lock-plugin jar:lib/gradle-extra-configurationsplugin jar:lib/gradle-git-scm-plugin jar:lib/gradle-info-plugin jar:lib/gradle-java-cross-compile-plugin jar:lib/gradle-lintplugin jar:lib/gradle-metrics-plugin jar:lib/gradle-ospackage-plugin jar:lib/gradle-override-plugin jar:lib/gradle-resolution-rulesplugin jar:lib/gradle-scm-plugin jar:lib/gradle-stash-plugin jar:lib/nebula-dependency-base-plugin jar:lib/nebula-dependencyrecommender jar:lib/nebula-grails-plugin jar:lib/nebula-project-plugin jar:lib/nebula-release-plugin jar:lib/gradle-release-1.2.jar:lib/ gradle-cobertura-plugin jar:lib/gretty-core jar:lib/spring-boot-loader-tools release.jar:lib/jetty-util v jar:lib/httpclientcache jar:lib/kotlin-stdlib jar:lib/metatron-decrypt jar:lib/nebula-publishing-plugin jar:lib/httpcore jar:lib/commonslogging-1.2.jar:lib/commons-codec-1.9.jar:lib/ivy jar:lib/build-info-extractor jar:lib/ant jar:lib/mail jar:lib/frigga-0.13.jar:lib/ nekohtml jar:lib/artifactory-java-client-api jar:lib/groovy-xml jar:lib/jcl-over-slf4j jar:lib/kotlin-stdlib-jre jar:lib/ svnkit jar:lib/asm-5.2.jar:lib/gpars jar:lib/junit-4.12.jar:lib/jackson-datatype-joda jar:lib/logstash-logback-encoder jar:lib/ jest jar:lib/fluent-hc jar:lib/redline jar:lib/jdeb-1.4.jar:lib/gradle-docker-plugin jar:lib/commons-beanutils-core jar:lib/jacksonmodule-kotlin jar:lib/maven-model-builder jar:lib/grails-launcher-1.1.jar:lib/groovy jar:lib/commons-cli-1.2.jar:lib/commonsconfiguration-1.10.jar:lib/org.apache.servicemix.bundles.bcprov-jdk _3.jar:lib/spring-boot-devtools release.jar:lib/spring-core release.jar:lib/ annotations-13.0.jar:lib/gson jar:lib/protobuf-java-util jar:lib/protobuf-java jar:lib/grpc-core jar:lib/javax.inject-1.jar:lib/metatroncommon jar:lib/metatron-ipc-common jar:lib/build-info-client jar:lib/xstream jar:lib/ant-launcher jar:lib/multiversecore jar:lib/jsr166y jar:lib/hamcrest-core-1.3.jar:lib/logback-core jar:lib/jest-common jar:lib/httpcore-nio jar:lib/ httpasyncclient-4.1.jar:lib/plexus-utils jar:lib/plexus-interpolation-1.24.jar:lib/plexus-component-annotations jar:lib/maven-model jar:lib/ maven-artifact jar:lib/maven-builder-support jar:lib/spring-boot release.jar:lib/spring-boot-autoconfigure release.jar:lib/ error_prone_annotations jar:lib/jsr jar:lib/grpc-context jar:lib/instrumentation-api jar:lib/grpc-protobuf jar:lib/grpcstub jar:lib/jackson-mapper-asl jar:lib/build-info-api jar:lib/xpp3_min-1.1.4c.jar:lib/spring-context release.jar:lib/grpc-google-commonprotos jar:lib/grpc-protobuf-lite jar:lib/jackson-core-asl jar:lib/spring-aop release.jar:lib/spring-beans release.jar:lib/springexpression release.jar:lib/aopalliance-1.0.jar:lib/http-builder jar:lib/json-lib-2.3-jdk15.jar:lib/xml-resolver-1.2.jar:lib/commonsbeanutils jar:lib/commons-collections jar:lib/ezmorph jar:lib/slf4j-api jar:lib/commons-io-2.5.jar:lib/jackson-annotations jar:lib/ jackson-databind jar:lib/nebula-gradle-interop jar:lib/org.eclipse.jgit.ui r.jar:lib/jsch.agentproxy.jsch jar:lib/ jsch.agentproxy.pageant jar:lib/jsch.agentproxy.sshagent jar:lib/jsch.agentproxy.usocket-jna jar:lib/jsch.agentproxy.usocket-nc jar:lib/ jsch.agentproxy.core jar:lib/jna jar:lib/jna-platform jar:lib/p4java jar:lib/jzlib jar:lib/jsch.agentproxy.svnkit-trileadssh jar:lib/trilead-ssh build220.jar:lib/jsch.agentproxy.connector-factory jar:lib/sequence-library jar:lib/sqljet jar:lib/antlrruntime-3.4.jar:lib/commons-lang3-3.5.jar:lib/gradle-git jar:lib/groovy-json jar:lib/commons-compress-1.8.jar:lib/bcpg-jdk15on-1.51.jar:lib/bcprovjdk15on-1.51.jar:lib/xercesimpl jar:lib/jackson-core jar:lib/org.eclipse.jgit r.jar:lib/javaewah jar:lib/jsch jar:lib/ grgit jar:lib/xz-1.5.jar

3 Module primer. module easytext.cli { } requires easytext.analysis; module easytext.analysis { exports analysis.api; opens impl; } easytext.cli easytext.analysis analysis.api reflection only! impl other

4 Module primer. module easytext.cli { } requires easytext.analysis; module easytext.analysis { } exports analysis.api; Modules define dependencies opens impl; explicitly easytext.cli easytext.analysis analysis.api reflection only! impl other

5 Module primer. module easytext.cli { } requires easytext.analysis; Packages are encapsulated by default module easytext.analysis { exports analysis.api; opens impl; } easytext.cli easytext.analysis analysis.api reflection only! impl other

6 Module primer. module easytext.cli { } requires easytext.analysis; Packages can be opened for deep reflection at run-time module easytext.analysis { exports analysis.api; opens impl; } easytext.cli easytext.analysis analysis.api reflection only! impl other

7 Migrating to Java 9. Java 8 java -cp -jar MyApp.jar Java 9 java -cp -jar MyApp.jar

8 Our journey to modules. 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. import javax.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 module graph.

12 java.se vs java.se.ee

13 Resolving JAXB. java --add-modules java.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 time Reflection on public Deep reflection Exports Open Exports + Open

16 Fixing illegal deep reflection. 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 Automatic Modules

18 But we re still on the classpath!

19 Let s migrate our code to modules But how do we deal with libraries?

20 package demo; import com.fasterxml.jackson.databind.objectmapper; public class 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 nonmodular JAR on the module path Exports all packages Requires all resolved modules Can read the class path (the unnamed module)

22 module books { } requires jackson.databind; CP=lib/jackson-annotations jar: CP+=lib/jackson-core jar javac -cp $CP --module-path mods -d out --module-source-path src -m books

23 Case study

24 Sample app after migration.

25 !"" 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 Step 1 - Project structure. 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. Compilation error BookstoreServiceImpl.java:7: error: package org.springframework.stereotype is not visible import org.springframework.stereotype.component; Our module needs explicit dependencies!

27 Step 3 - Add missing compile time platform modules. Compilation error HibernateBooksService.java:19: error: cannot access Referenceable return sessionfactory.getcurrentsession().get(bookentity.class, id); ^ class file for javax.naming.referenceable not found Hibernate should declare requires transitive java.naming

28 Running. java -cp $CLASSPATH --module-path mods: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 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 Refactor to multiple modules

33 Multi module structure

34 requires books.api books.impl main requires bookstore requires Spring

35 requires books.api books.impl main requires bookstore.api bookstore.impl requires provides uses Module System provides

36 Build tools. module bookstore { requires books; <artifactid>bookstore</artifactid> <build> <plugins> <plugin> <groupid>org.apache.maven.plugins</groupid> <artifactid>maven-compiler-plugin</artifactid> <configuration> <source>9</source> exports bookstore.service.api; <target>9</target> </configuration> uses books.api.service.booksservice; </plugin> </plugins> provides bookstore.service.api.bookstoreservice with </build> bookstore.service.impl.bookstoreserviceimpl; <dependencies> } <dependency> <groupid>javamodularity</groupid> <artifactid>books</artifactid> <version>1.0-snapshot</version> </dependency> </dependencies>

37 Thank you. Paul