so, you wanna migrate to java 9?
TRANSCRIPT
So, you wannamigrate to Java9?
by Tomek Adamczewski
13/11/2017
Where are we?
2
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
Cool features of Java 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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
“Think trains, not limousines”
4
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
5
Con
fiden
tial /
Res
trict
ed /
Publ
ic
Pres
enta
tion
or p
art t
itle
13/1
1/20
17Definition of Done
• Code compiles• New features merged to the master branch• All tests pass• The task is documented and closed
16
CodeCompiles
jig·saw [jig-saw] n.a complicated problem consisting of many different parts
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
There are no silver bullets
A lot of libraries or plugins are not compatible with Java 9 yet
7
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
Useful tools
$ jdeps --jdk-internals -R --class-path ‘lib/*’ guava-HEAD-jre-SNAPSHOT.jarsplit package: javax.annotation [jrt:/java.xml.ws.annotation, lib/jsr305-1.3.9.jar]
guava-HEAD-jre-SNAPSHOT.jar -> jdk.unsupportedcom.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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
…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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
…and hacks
java① --add-opens java.base/java.lang=ALL-UNNAMED② --add-modules java.xml.ws.annotation③ --patch-module java.xml.ws.annotation=jsr305-3.0.2.jar
--class-path $dependencies-jar $appjar
10
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
211
Code Compiles
New keyword
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
JEP 302: Lambda Leftovers
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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
BiFunction<Integer, String, String> biss = (i, _) -> String.valueOf(i);
Sonar to the rescue!™
13
Con
fiden
tial /
Res
trict
ed /
Publ
ic
Pres
enta
tion
or p
art t
itle
13/1
1/20
17
Yet another tool to cope with?
14
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
…not really!
15
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
316
New feature merged to the master branch
Things might fail or they might not fail
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
Map<String, Integer> fooBar = Map.ofEntries(entry("foo", 1), entry("bar", 2),
// (...) entry("baz", 42));
We’ve all done it before, didn’t we?
@SafeVarargspublic 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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
private static final Map<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 studyC
onfid
entia
l / R
estri
cted
/ Pu
blic
Pres
enta
tion
or p
art t
itle
13/1
1/20
17
----------------------------------BUILD SUCCESS----------------------------------Total time: 01:08 min (Wall Clock)
20
Case studyC
onfid
entia
l / R
estri
cted
/ Pu
blic
Pres
enta
tion
or p
art t
itle
13/1
1/20
17
private static final 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)
Jenkins build-timeout plugin
21
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
Possible strategies
• Absolute• Deadline• Elastic• Likely stuck• No Activity
Possible actions
• Abort• Fail• Abort and restart• Write build description
422
All tests pass
Things might fail…but they also might not fail
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
You can “unit” test your performance
@Testpublic void testPerf() throws Exception {
Result result = benchmark(4, 1000,(thread, pass) -> singlePass(thread, pass));
LOG.info(Table.print(result));
assertExecTimes(result);}
24
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
Ugly? But it’s up 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
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
526
The task is documented and closed
In case you just woke up…
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
Brace yourself
Java WILL be updated every 6 months. Make sure you’re armed and ready
27
Con
fiden
tial /
Res
trict
ed /
Publ
icPr
esen
tatio
n or
par
t titl
e13
/11/
2017
