Java 9 and the impact on Maven Projects (Devoxx 2016)

Java 9 and the impact on Maven Projects (Devoxx 2016)

• 1.
  @rfscholte#Devoxx #Maven Java 9and the impact on Maven Projects Robert Scholte Chairman Apache Maven CGI
• 2.
  @rfscholte#Devoxx #Maven Tools inActions • Migrating an example project to Java9
• 3.
  @rfscholte#Devoxx #Maven History April 2014:Java 9 Early Access releases No remarkable issues when running with Maven September 2015: Jigsaw Early Access releases 99%+ of the Java Maven projects failed to compile OpenJDK fixed issue and released within 72h! zero LOCs changed in Maven core codebase to run on Java 9
• 4.
  @rfscholte#Devoxx #Maven Maven byExample Chapter 7 Multi-Module Enterprise Project “In this chapter, we create a multi-module project that evolves the examples from Chapter 6 and Chapter 5 into a project that uses the Spring Framework and Hibernate to create both a simple web application and a command-line utility to read data from the Yahoo Weather feed.”
• 5.
  @rfscholte#Devoxx #Maven Multi-Module EnterpriseProject Adjustments: • Added m-shade-plugin to :simple-command • Locked maven-jar-plugin to latest 2.x (= 2.6) • Locked maven-war-plugin to latest 2.x (=2.6) • Add hbm2ddl=create persist config-files
• 6.
  @rfscholte#Devoxx #Maven Baseline • Maven3.4.0-SNAPSHOT (colorized output) • JDK 1.8.0_040 / jigsaw-jdk-9-ea+142
• 7.
  @rfscholte#Devoxx #Maven Source /Target option 1.5 is no longer supported. Java 5 compatible? • Configure maven-toolchain-plugin Java 6 compatible? • Set source/target to 1.6 • Replace source/target with release 6 • (requires maven-compiler-plugin 3.6.0)
• 8.
  @rfscholte#Devoxx #Maven Caused by:j.l.AIOOBException: 1 JEP 223: New Version-String Scheme (project Verona) System Property Existing Proposed java.version 1.9.0 9 java.runtime.version 1.9.0-b100 9+100 java.vm.version 1.9.0-b100 9+100 java.specification.version 1.9 9 java.vm.specification.version 1.9 9
• 9.
  @rfscholte#Devoxx #Maven version.split(“.”)[1] maven-archiver-3.0.1 - maven-jar-plugin-3.0.0 -maven-war-plugin-3.0.0 - maven-ear-plugin-xxx - maven-assembly-plugin-xxx maven-javadoc-plugin-2.10.4 …
• 10.
  @rfscholte#Devoxx #Maven j.l.reflect.InaccessibleObjectExcepti on jigsaw-jdk-9-ea+135 #AwkwardStrongEncapsulation Options: •Xstream fix (not available yet) • Improved support project Jigsaw • maven-war-plugin could think of other implementation • Don’t create war • Use jigsaw-jdk-9-ea+134 or earlier as Maven JRE (but compile with jigsaw-jdk-9-ea+141)
• 11.
  @rfscholte#Devoxx #Maven modules arenot supported in -source 1.6 Options: • Set release=9 • Apply recipe “Older projects with module-info” • maven-compiler-plugin with 2 execution-blocks
• 12.
  @rfscholte#Devoxx #Maven Split packages “Iftwo or more JAR files on the class path contain types in the same package then at most one of them can be used as an automatic module, since the module system still guarantees that every named module reads at most one named module defining a given package and that named modules defining identically-named packages do not interfere with each other.” Option (just one): upgrade/replace dependencies
• 13.
  @rfscholte#Devoxx #Maven How tocontinue • Not all Java9/jigsaw changes are related to Maven • There will be Maven recipes to help migrating to Java 9
• 14.
  @rfscholte#Devoxx #Maven Thank you Java9 and the impact on Maven Projects Robert Scholte Please rate & give feedback on this talk