JuanMorenoDeveloper / java-11-upgrade-certification-practice

Java 11 1Z0-817 Exam Exercises

java-11-upgrade-certification-practice

Sample code to practice for the 1Z0-817 exam

Build custom runtime image with jlink

Build: jlink --module-path people/target/people-0.0.1-SNAPSHOT.jar:conversation/target/conversation-0.0.1-SNAPSHOT.jar:greeting/target/greeting-0.0.1-SNAPSHOT.jar:$JAVA_HOME/jmods --add-modules greeting --output myimage

Optimize image: jlink --module-path people/target/people-0.0.1-SNAPSHOT.jar:conversation/target/conversation-0.0.1-SNAPSHOT.jar:greeting/target/greeting-0.0.1-SNAPSHOT.jar:$JAVA_HOME/jmods --add-modules greeting --strip-debug --compress=2 --output myimagecompress

Run: myimage/bin/java -m greeting/com.main.Main

Migration with jdeps

Show dependencies: jdeps -R -summary --module-path conversation/target/conversation-0.0.1-SNAPSHOT.jar:people/target/people-0.0.1-SNAPSHOT.jar greeting/target/greeting-0.0.1-SNAPSHOT.jar

Generate module-info.java: jdeps --generate-module-info module-info-files lib/* dist/*

Strategies:

1.- Break cyclic dependencies and split packages with refactor and new modules. 2.- Top-down migration (Migrate application first, libraries latter) 3.- Bottom-up migration (Library first, application latter)

MRJAR

See config in people module's pom.xml.

Inheritance rules of default methods

1. A superclass method takes priority over an interface default method.
2. A subtype interface's default method takes priority over a supertype interface's default method.
3. If there a conflict, treat the default method as abstract.

Check deprecation APIs

jdeprscan

Usage: jdeprscan [options] {dir|jar|class} ...

options:
        --class-path PATH
        --for-removal
        --full-version
  -? -h --help
  -l    --list
        --release 6|7|8|9|10|11
  -v    --verbose
        --version

Compilation

mvn clean package -> Require Java 12 onwards.

Main module execution

java -jar -p people/target/people-0.0.1-SNAPSHOT.jar:main/target/main-0.0.1-SNAPSHOT.jar:header/target/header-0.0.1-SNAPSHOT.jar:greeting/target/greeting-0.0.1-SNAPSHOT.jar:spanish/target/spanish-0.0.1-SNAPSHOT.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.10.2/jackson-databind-2.10.2.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.10.2/jackson-annotations-2.10.2.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.10.2/jackson-core-2.10.2.jar -m main/com.main.Main

Main module diagram