JDK 14 is full of great new features for developers. In this presentation, we'll take you through what they are and how to use them.

1. © Copyright Azul Systems 2020
© Copyright Azul Systems 2015
@speakjava
JDK 14:
Lots of New Features
Simon Ritter
Deputy CTO, Azul Systems
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OpenJDK: New Release Model
 A new version of the JDK is released every six months
– March and September
– 2018: JDK 10 and 11, 2019: JDK 12 and 13
– Continuing this year with JDK 14 and JDK 15
 OpenJDK development is more agile
 Features are only included when ready
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Incubators And Previews
 Add new features to OpenJDK
 Without making it standard
 Time for feedback and changes (or removal)
 Incubator modules (JEP 11)
 API and tool changes
 Started in JDK 9 with HTTP/2
 Preview features (JEP 12)
 Language and VM changes
 Started in JDK 12 with switch expression
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JDK 14: Big Features
 Language level
– JEP 359: Records (preview)
– JEP 305: Pattern matching for instanceof (preview)
– JEP 368: Text blocks (second preview)
 API Changes
– Record related changes
– Foreign memory access API (incubator module)
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Simple Java Data Class
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class Point {
private final double x;
private final double y;
public Point(double x, double y) {
this.x = x;
this.y = y;
}
public double getX() {
return x;
}
public double getY() {
return y;
}
}

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Records (Preview)
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record Point(double x, double y) { }
record Range(double low, double high) {
public Range {
if (low > high)
throw new IllegalArgumentException("Bad values");
}
public String toString() {
return "Point is (" + x + ", " + y + ")";
}
}

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Using instanceof
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if (obj instanceof String) {
String s = (String)obj;
System.out.println(s.length());
}

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Pattern Matching instanceof (Preview)
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if (obj instanceof String s) {
System.out.println(s.length());
} else {
// Use of s not allowed here
}
if (obj instanceof String s && s.length() > 0)
System.out.println(s.length());
// Compiler error
if (obj instanceof String s || s.length() > 0)
System.out.println(s.length());

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Pattern Matching instanceof (Preview)
if (!(o instanceof String s))
return;
System.out.println(s.length());

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Text Blocks (Second Preview)
 Two new escape sequences
String continuous = """This line will not
contain a newline in the middle""";
String colours = """Red s
greens
blue s
""";

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Switch Expression
 JEP 361: Switch Expressions (standard)
– No more changes from the second preview (JDK 13)
– Now a standard feature in JDK 14
 No --enable-preview flag necessary
 Included in the Java SE specification
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Helpful NullPointerException
 Who's never had an NullPointerException?
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a.b.c.i = 99;
Exception in thread "main" java.lang.NullPointerException
at Prog.main(Prog.java:5)
Exception in thread "main" java.lang.NullPointerException:
Cannot read field "c" because "a.b" is null
at Prog.main(Prog.java:5)

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Other Feature JEPs
 343: Packaging tool (incubator)
 345: NUMA aware memory allocation for G1
 349: Java Flight Recorder streaming events
 352: Non-volatile mapped byte buffers
 364/365: ZGC on Windows/macOS
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Deprecation and Removal JEPs
 363: Remove the CMS collector
 362: Deprecate the Solaris and SPARC ports
 366: Deprecate ParallelScavenge + SerialOld GC combo
 367: Remove the Pack200 tools and API
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API Changes

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Foreign-Memory Access API
 Alternative to parts of sun.misc.Unsafe and
MappedByteBuffer
– MemorySegment
– MemoryAddress
– MemoryLayout
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Record Related APIs
 Class
 isRecord()
 RecordComponent[] getRecordComponents()
 java.lang.Record
 java.lang.annotation.ElementType
 RECORD_TYPE
 java.lang.runtime
 New package for records
 ObjectMethods class with bootstrap()
 javax.lang.mode.util new classes
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Serial Annotation
 Used for compiler checks of Serializable classes
 Use with these methods
 writeObject
 readObject
 readObjectNoData
 writeReplace
 readResolve
 And these fields
 serialPersistentFields
 serialVersionUID
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Miscellaneous
 NullPointerException
 Now overrides getMessage() from Throwable
 StrictMath
 New exact methods: incrementExact(), decrementExact(),
negateExact()
 CompactNumberFormat
 pluralRules()
 HashSet
 toArray()
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Azul's Zulu Java

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Zulu Community
 Azul’s FREE binary distribution of OpenJDK
 Passes all TCK tests
 Versions: JDK 6-14 available
 JDK 15 available as Early Access
 Wide platform support:
 Intel 64-bit Windows, Mac, Linux
 Intel 32-bit Windows and Linux
 ARM 32 and 64-bit
 PPC 32 and 64-bit
 Solaris 10/11 on SPARC
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www.azul.com/downloads/zulu

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Zulu Enterprise
 Backporting of bug fixes and security patches from
supported OpenJDK release
 Zulu 8 supported until end of 2030
 Zulu 6 supported until end of 2021
 LTS releases have 8 years active + 2 years passive support
 Medium Term Support releases
– Two interim releases between LTS releases (13, 15...)
– Bridge to LTS releases
– Supported until 18 months after next LTS release
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Summary

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JDK 14: A Great Release
 Powerful new language features
– Records
– Pattern matching for instanceof
 Better NullPointerException messages
 Useful API changes
– Foreign memory access API
 Keeping Java fresh after 25 years!
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25. © Copyright Azul Systems 2020
© Copyright Azul Systems 2015
@speakjava
Thank You!
Simon Ritter
Deputy CTO, Azul Systems
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