The document outlines the features and improvements introduced in JDK 14, including new language features like records, pattern matching for instanceof, and text blocks. It also discusses changes in the API, particularly the foreign memory access API, and improvements such as better null pointer exception messages. The release model of OpenJDK emphasizes a biannual update with agile development, ensuring features are included only when ready.

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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2. © Copyright Azul Systems 2020
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

24. © Copyright Azul Systems 2020
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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