Java features. Java 8, 9, 10, 11
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The document discusses the new features introduced in Java versions 8 through 11. It provides 10 examples of features added in Java 9, including private methods in interfaces and collection factory methods. Another section outlines 6 features from Java 10 such as local variable type inference. Finally, Java 11 features like local-variable syntax for lambda parameters and the standardization of the HTTP client are presented along with various API improvements and removed features.
![12/5/19
Java 9 Features with Examples
10. Compact Strings Improvement
➢
Prior to Java 9, string data was stored as an array of chars. This required 16 bits for each char.
public final class String implements java.io.Serializable, Comparable<String>, CharSequence {
//The value is used for character storage.
private final char value[ ];
}
➢
Starting with Java 9, strings are now internally represented using a byte array along with a flag field for
encoding references.
public final class String implements java.io.Serializable, Comparable<String>, CharSequence {
/** The value is used for character storage. */
private final byte[] value;
private final byte coder;
}
Reference: JEP 280
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![12/5/19
Java 11 Features with Examples
5. New APIs
●
java.io.ByteArrayOutputStream
- void writeBytes(byte[]): Write all the bytes of the parameter to the output stream
●
java.io.FileReader
- Two new constructors that allow a Charset to be specified.
●
java.io.FileWriter
- Four new constructors that allow a Charset to be specified.
●
java.io.InputStream
- io.InputStream nullInputStream()
●
java.io.OutputStream
- io.OutputStream nullOutputStream()
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java.io.Reader
- io.Reader nullReader()
●
java.io.Writer
- io.Writer nullWriter()
●
java.lang.String
- boolean isBlank(), Stream lines(), String repeat(int), String strip(), String stripLeading(), String
stripTrailing()
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![12/5/19
Java 11 Features with Examples
●
java.lang.Thread:
- destroy() and stop(Throwable) methods have been removed
●
java.nio.file.Files
- String readString(Path): Reads all content from a file into a string, decoding from bytes to characters
using the UTF-8 charset.
- String readString(Path,Charset): As above, except decoding from bytes to characters using the
specified Charset.
- Path writeString(Path, CharSequence, java.nio.file. OpenOption[]:Write a CharSequence to a file.
Characters are encoded into bytes using the UTF-8 charset.
- PathwriteString(Path,CharSequence,java.nio.file.Charset, OpenOption[]: As above, except Characters
are encoded into bytes using the specified Charset.
●
java.nio.file.Path
- Path of(String, String[]): Returns a Path by converting a path string, or a sequence of strings that when
joined form a path string.
- Path of(net.URI): Returns a Path by converting a URI.
●
java.util.Collection
- Object[] toArray(java.util.function.IntFunction): Returns an array containing all of the elements in this
collection, using the provided generator function to allocate the returned array.
●
java.util.function.Predicate
- Predicate not(Predicate)
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Java features. Java 8, 9, 10, 11
- 1. 12/5/19 Java 8, 9, 10, 11. Delivering New Feature in the JDK Ivelin Yanev INTRODUCTION
- 2. 12/5/19 Delivery process 2 Old delivery process
- 3. 12/5/19 Delivery process 3 New delivery process
- 5. 12/5/19 Other JDKs ➢ OracleJDK: Free and supported to 6 months ➢ LTS versions have extended ($$$) support by Oracle ➢ Identical to OpenJDK when free ➢ OpenJDK: Free forever, not supported after 6 months ➢ Built by https://adoptopenjdk.net/ ➢ Other JVMs (Azul, IBM, RedHat, etc.) 5
- 6. 12/5/19 Java 9 Features with Examples 1 . Private Methods in Interfaces Java 7 - Constant variables - Abstract methods Java 8 - Constant variables - Abstract methods - Default methods - Static methods Java 9 Interface Changes - Constant variables - Abstract methods - Default methods - Static methods - Private methods - Private Static methods Reference: JEP 213 6
- 7. 12/5/19 Java 9 Features with Examples 2. Collection Factory Methods - Defines several factory methods (.of(…)) on the List, Set, and Map interfaces for conveniently creating instances of unmodifiable collections and maps with small numbers of elements. - Map.of() is not a varargs method. There are only overloaded Map.of() for up to 10 entries. For a case where we have more than 10 key-value pairs, there is a different method: static <K,V> Map<K,V> ofEntries(Map.Entry<? extends K,? extends V>... entries) Reference: JEP 269 7
- 8. 12/5/19 Java 9 Features with Examples 3. Try-With-Resources Improvements Before Java 9 FileInputStream fis = new FileInputStream("movie.mp4"); try (FileInputStream fis2 = fis) { //….. } catch (IOException e) { // ... } Reference: JEP 213 8 Java 9+ FileInputStream fis = new FileInputStream("movie.mp4"); try (fis) { //….. } catch (IOException e) { // ... }
- 9. 12/5/19 Java 9 Features with Examples 4. Process API Improvements Two new interfcase in Process API: java.lang.ProcessHandle java.lang.ProcessHandle.Info The ProcessHandle provides: - The process ID: process.getPid() - Arguments - Command - Start time - Accumulated CPU time - User - Parent process With the ProcessHandle.onExit method, the asynchronous mechanisms of the CompletableFuture class can perform an action when the process exits. Reference: JEP 102 9
- 10. 12/5/19 Java 9 Features with Examples 5. New Http client API > The API consists of 3 core classes: HttpRequest – represents the request to be sent via the HttpClient HttpClient – behaves as a container for configuration information common to multiple requests HttpResponse – represents the result of an HttpRequest call > Send Requests – Sync vs. Async send(…) – synchronously (blocks until the response comes) sendAsync(…) – asynchronously (doesn’t wait for response, non-blocking) Reference: JEP 110 10
- 11. 12/5/19 Java 9 Features with Examples 6. Optional Class Improvements ● stream() method: ● public Stream<T> stream() ● ifPresentOrElse() method: ● public void ifPresentOrElse(Consumer<? super T> action, Runnable emptyAction) ● or() method: ● public Optional<T> or(Supplier<? extends Optional<? extends T>> supplier) Reference: JEP-213 11
- 12. 12/5/19 Java 9 Features with Examples 7. Enhanced @Deprecated annotation @Deprecated annotation provides better information about the status and intended future of APIs: ➢ forRemoval(): ● This returns a boolean to indicate whether this API element is intended for removal in some future release. ● E.g. @Deprecated(forRemoval=true) indicates the API will be removed in the next release of the Java SE platform. ➢ Since(): ● This returns the release or version number, as a string, when this API element was first marked as deprecated @Deprecated(since="9", forRemoval=true) Reference: JEP 277 12
- 13. 12/5/19 Java 9 Features with Examples 8. G1 (Default Garbage Collector) Reference: JEP 248 13
- 14. 12/5/19 Java 9 Features with Examples 9. StackWalker API ➢ New API for easier manipulation of stack traces ➢ Provided by the java.lang.StackWalker class Reference: JEP 259 14
- 15. 12/5/19 Java 9 Features with Examples 10. Compact Strings Improvement ➢ Prior to Java 9, string data was stored as an array of chars. This required 16 bits for each char. public final class String implements java.io.Serializable, Comparable<String>, CharSequence { //The value is used for character storage. private final char value[ ]; } ➢ Starting with Java 9, strings are now internally represented using a byte array along with a flag field for encoding references. public final class String implements java.io.Serializable, Comparable<String>, CharSequence { /** The value is used for character storage. */ private final byte[] value; private final byte coder; } Reference: JEP 280 15
- 16. 12/5/19 Java 10 Features with Examples 1. JEP 286: Local Variable Type Inference var list = new ArrayList<String>(); // infers ArrayList<String> var stream = list.stream(); // infers Stream<String> 2. JEP 307: Parallel Full GC for G1 3. Collection Changes java.util.List: E> List<E> copyOf(Collection<? extends E> coll) java.util.Set: <E> Set<E> copyOf(Collection<? extends E> coll) java.util.Map: <K,V> Map<K,V> copyOf(Map<? extends K, ? extends V> coll) 16
- 17. 12/5/19 Java 11 Features with Examples 1. JEP 323: Local-Variable Syntax for Lambda Parameters list.stream() .map((var s) -> s.toLowerCase()) .collect(Collectors.toList()); list.stream() .map((@Notnull var s) -> s.toLowerCase()) .collect(Collectors.toList()); 2. JEP 330: Launch Single-File Source-Code Programs java HelloWorld.java 3. JEP 321: HTTP Client (Standard) ➢ HTTP/2 support ➢ Incubating module from JDK 9 standardised 4. JEP 320: Remove The Java EE and CORBA Modules 17
- 18. 12/5/19 Java 11 Features with Examples 5. New APIs ● java.io.ByteArrayOutputStream - void writeBytes(byte[]): Write all the bytes of the parameter to the output stream ● java.io.FileReader - Two new constructors that allow a Charset to be specified. ● java.io.FileWriter - Four new constructors that allow a Charset to be specified. ● java.io.InputStream - io.InputStream nullInputStream() ● java.io.OutputStream - io.OutputStream nullOutputStream() ● java.io.Reader - io.Reader nullReader() ● java.io.Writer - io.Writer nullWriter() ● java.lang.String - boolean isBlank(), Stream lines(), String repeat(int), String strip(), String stripLeading(), String stripTrailing() 18
- 19. 12/5/19 Java 11 Features with Examples ● java.lang.Thread: - destroy() and stop(Throwable) methods have been removed ● java.nio.file.Files - String readString(Path): Reads all content from a file into a string, decoding from bytes to characters using the UTF-8 charset. - String readString(Path,Charset): As above, except decoding from bytes to characters using the specified Charset. - Path writeString(Path, CharSequence, java.nio.file. OpenOption[]:Write a CharSequence to a file. Characters are encoded into bytes using the UTF-8 charset. - PathwriteString(Path,CharSequence,java.nio.file.Charset, OpenOption[]: As above, except Characters are encoded into bytes using the specified Charset. ● java.nio.file.Path - Path of(String, String[]): Returns a Path by converting a path string, or a sequence of strings that when joined form a path string. - Path of(net.URI): Returns a Path by converting a URI. ● java.util.Collection - Object[] toArray(java.util.function.IntFunction): Returns an array containing all of the elements in this collection, using the provided generator function to allocate the returned array. ● java.util.function.Predicate - Predicate not(Predicate) 19
- 20. 12/5/19 Java 11 Features with Examples 20 6. Removed Features ● Removal of sun.misc.Unsafe.defineClass: Users should use the public replacement, java.lang.invoke.MethodHandles.Lookup.defineClass ● Removal of JavaFX from the Oracle JDK ● …………
- 21. 12/5/19 Java 11 Features with Examples ● 7. How much faster is Java 11?