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![1
6
Code
Compiles
jig·saw [jig-saw] n.
a complicated problem consisting of many
different parts
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13/11/2017](https://image.slidesharecdn.com/migratetoj9-171113170620/85/So-you-wanna-migrate-to-Java-9-6-320.jpg)
![Useful tools
$ jdeps --jdk-internals -R --class-path ‘lib/*’ guava-HEAD-jre-SNAPSHOT.jar
split package: javax.annotation [jrt:/java.xml.ws.annotation, lib/jsr305-1.3.9.jar]
guava-HEAD-jre-SNAPSHOT.jar -> jdk.unsupported
com.google.common.cache.Striped64 -> sun.misc.Unsafe
JDK internal API (jdk.unsupported)
com.google.common.cache.Striped64$1 -> sun.misc.Unsafe
JDK internal API (jdk.unsupported)
(…)
JDK Internal API Suggested Replacement
---------------- ---------------------
sun.misc.Unsafe See http://openjdk.java.net/jeps/260
8
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So, you wanna migrate to Java 9?
- 1. So, you wanna migrateto Java9? by Tomek Adamczewski 13/11/2017
- 2.
- 3. Cool features ofJava 9 • Project Jigsaw • JShell • Enhanced Collections framework • Enhanced @Deprecated • Project Coin improvements • Support for cgroup limits (think: docker) • G1GC improvements • Changes to JDK Release Model 3 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 4. “Think trains, notlimousines” 4 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 5. 5 Confidential/Restricted/Public Presentationorparttitle 13/11/2017 Definition ofDone • Code compiles • New features merged to the master branch • All tests pass • The task is documented and closed
- 6. 1 6 Code Compiles jig·saw [jig-saw] n. acomplicated problem consisting of many different parts Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 7. There are nosilver bullets A lot of libraries or plugins are not compatible with Java 9 yet 7 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 8. Useful tools $ jdeps--jdk-internals -R --class-path ‘lib/*’ guava-HEAD-jre-SNAPSHOT.jar split package: javax.annotation [jrt:/java.xml.ws.annotation, lib/jsr305-1.3.9.jar] guava-HEAD-jre-SNAPSHOT.jar -> jdk.unsupported com.google.common.cache.Striped64 -> sun.misc.Unsafe JDK internal API (jdk.unsupported) com.google.common.cache.Striped64$1 -> sun.misc.Unsafe JDK internal API (jdk.unsupported) (…) JDK Internal API Suggested Replacement ---------------- --------------------- sun.misc.Unsafe See http://openjdk.java.net/jeps/260 8 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 9. …and hacks <artifactId>maven-compiler-plugin</artifactId> <version>3.7.0</version> <configuration> - <source>1.8</source> -<target>1.8</target> + <source>9</source> + <target>9</target> + <compilerArgs> + <arg>--add-exports</arg> + <arg>java.base/sun.security.jca=ALL-UNNAMED</arg> + </compilerArgs> </configuration> 9 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 10. …and hacks java ① --add-opensjava.base/java.lang=ALL-UNNAMED ② --add-modules java.xml.ws.annotation ③ --patch-module java.xml.ws.annotation=jsr305-3.0.2.jar --class-path $dependencies -jar $appjar 10 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 11.
- 12. JEP 302: LambdaLeftovers Treatment of underscores In many languages, it is common to use an underscore (_) to denote an unnamed lambda parameter (and similarly for method and exception parameters): (…) Phase 2 came in Java 9, when this warning became an error. 12 Confidential/Restricted/Public Presentationorparttitle 13/11/2017 BiFunction<Integer, String, String> biss = (i, _) -> String.valueOf(i);
- 13. Sonar to therescue!™ 13 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 14. Yet another toolto cope with? 14 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 15.
- 16. 3 16 New feature merged tothe master branch Things might fail or they might not fail Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 17. Enhanced Collections framework static<K,V> Map<K,V> of() static <K,V> Map<K,V> of(K k1, V v1) static <K,V> Map<K,V> of(K k1, V v1, K k2, V v2) static <K,V> Map<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3) static <K,V> Map<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7, K k8, V v8, K k9, V v9, K k10, V v10) static <K,V> Map<K,V> ofEntries(Map.Entry<? extends K,? extends V>... entries) 17 Confidential/Restricted/Public Presentationorparttitle 13/11/2017 Map<String, Integer> fooBar = Map.ofEntries( entry("foo", 1), entry("bar", 2), // (...) entry("baz", 42));
- 18. We’ve all doneit before, didn’t we? @SafeVarargs public static <K, V> Map<K, V> map(Entry<K, ? extends V>... entries) { return stream(entries) .filter(Objects::nonNull) .collect(toMap(Entry::getKey, Entry::getValue)); } 18 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 19. private static finalMap<String, ErrorReason> ERROR_REASON_MAPPER = map( entry("1001", Format_Incorrect), entry("1002", Format_Expiry_Date_Incorrect), // 95 more entries entry(”6027", Entity_Already_Active)); 19 Case studyConfidential/Restricted/Public Presentationorparttitle 13/11/2017 ---------------------------------- BUILD SUCCESS ---------------------------------- Total time: 01:08 min (Wall Clock)
- 20. 20 Case studyConfidential/Restricted/Public Presentationorparttitle 13/11/2017 private staticfinal Map<String, ErrorReason> ERROR_REASON_MAPPER = MapUtils.<String, ErrorReason>map( //explicit generics improve compile time by ~50s entry("1001", Format_Incorrect), entry("1002", Format_Expiry_Date_Incorrect), // 95 more entries entry(”6027", Entity_Already_Active)); ---------------------------------- BUILD SUCCESS ---------------------------------- Total time: 10.556 s (Wall Clock)
- 21. Jenkins build-timeout plugin 21 Confidential/Restricted/Public Presentationorparttitle 13/11/2017 Possiblestrategies • Absolute • Deadline • Elastic • Likely stuck • No Activity Possible actions • Abort • Fail • Abort and restart • Write build description
- 22. 4 22 All tests pass Thingsmight fail… but they also might not fail Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 23. OptUtils /** @return ofNullable(t).map(provider).orElseGet(supplier)*/ public static <T, R> R optGet( T t, Function<T, R> provider, Supplier<R> supplier) { return ofNullable(t).map(provider).orElseGet(supplier); } 23 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 24. You can “unit”test your performance @Test public void testPerf() throws Exception { Result result = benchmark(4, 1000, (thread, pass) -> singlePass(thread, pass)); LOG.info(Table.print(result)); assertExecTimes(result); } 24 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 25. Ugly? But it’sup to 10x faster… /** @return ofNullable(t).map(provider).orElseGet(supplier) */ public static <T, R> R optGet( T t, Function<T, R> provider, Supplier<R> supplier) { return t == null ? supplier.get() : optGet(provider.apply(t), supplier); } /** @return ofNullable(t).orElseGet(supplier) */ public static <T> T optGet(T t, Supplier<T> supplier) { return t == null ? supplier.get() : t; } 25 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 26. 5 26 The task isdocumented and closed In case you just woke up… Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 27. Brace yourself Java WILLbe updated every 6 months. Make sure you’re armed and ready 27 Confidential/Restricted/Public Presentationorparttitle 13/11/2017
- 28.