What's new in JDK 10(my short version)

Link to the Oracle release notes: Oracle Release Notes

New Features
- java-util: Optional.orElseThrow() - preferred alternative to get()
- APIs for Creating Unmodifiable Collections: List.copyOf, Set.copyOf, Map.copyOf.
Stream Collectors have additional have additional toUnmodifiableList, toUnmodifiableSet, toUnmodifiableMap methods.
- System property to disable JRE last usage tracking
- Hashed passwords for out of the box JMX Agent in jmxremote.password using SHA3-512
- Garbage collection: improvement in G1 worst-case latencies by making the full GC parallel.
- Root certificates: added certificates to the cacerts keystore so that TLS connections can be established
- TLS Session Hash and Extended Master Secret Extension Support
- bytecode generation improvement for Loop
- Javadoc tool additions, like --add-stylesheet, --overridden-methods=value, @summary tag for usage in specifying the text summary of the API description.

Java Specification Request (JSR) 383: Source

Java Enhancement Proposal (JEP) 314:
- In addition to Java SE 9 added ca and nu BCP 47 U Language-tag extensions, JEP 314 added:
a) cu (currency type)
b) fw (first day of week)
c) rg (region override)
d) tz (time zone)

JEP 322: Time-Based Release Versioning
Necessary for the six-month release cadence
$FEATURE.$INTERIM.$UPDATE.$PATCH
compared to Java 9 Release Scheme:
$MAJOR.$MINOR.$SECURITY

$FEATURE is incremented every six months.
$INTERIM is always zero, since the six-month model does not include interim releases. We reserve it here for flexibility
$UPDATE is incremented one month after $FEATURE is incremented, and every three months thereafter
$PATCH — The emergency patch-release counter, incremented only when it's necessary to produce an emergency release to fix a critical issue.

JEP 286: Local-Variable Type Inference
Infer type to declarations of local variables with initializers. Examples:

var list = new ArrayList<String>();
var stream = list.stream();

Removed Features:
- javax.swing: Removal of Swing Old LookAndFeel
- java.lang: Removal of Runtime.getLocalizedInputStream and Runtime.getLocalizedOutputStream.
- java.rmi: removal of RMI server-side multiplex protocol support
- Removal of common DOM APIs: com.sun.java.browser.plugin2.DOM and sun.plugin.dom.DOMObject
- Removal of FlatProfiler, which was enabled by settings the -Xprof VM argument
- Removal of Obsolete -X Options: -Xoss, -Xsqnopause, -Xoptimize, -Xboundthreads, -Xusealtsigs
- Removal of javafx/application-lifecycle: HostServices::getWebContext method
- javafx/graphics: Removal of T2K Rasterizer and ICU Layout Engine From JavaFX
- javafx/media: Removal of Deprecated VP6/FXM/FLV Code from Java FX
- java.security: Removal of Deprecated Pre-1.2 SecurityManager Methods and Fields
- java.security: Removal of policytool
- javax.security: Removal of Deprecated Classes in com.sun.security.auth.**
- javadoc: Removal of Old standard Doclet which outputs HTML content.
- Removal of the native-header generation tool javah
- Removal of Java Launcher Data model options -d32 and -d64

Deprecated Features and Options (forRemoval=true and forRemoval=false)
- jdk.snmp module (SNMP monitoring and management support for the JVM)
- java.security.{Certificate, Identity, IdentityScope, Signer}
- java.security.acl
- javax.security.auth.Policy

Other Notes:
- Class file version from 53(44+9) to 54(44+10)
- java.awt touch keyboard for Swing/AWT text components on Windows 8 or later.
- java.awt.TrayIcon.displayMessage() reimplemented on macOs to use standard notification center instead of a custom window
- Changes on how finalize calls close on FileInput/OutputStream (relaxation)
- -Xbootclasspath/a will make bootstrap class loader to skip empty element when locating resources
- RMI Registry Filter Allows binding arrays of any type now, and the maximum size increased to 1 million.
- Added javax.management.MBeanOperationInfo.MBeanOperationInfo impact parameter validation.
- TraceYoungGenTime and TraceOldGenTime have been removed. Same info available through Unified Logging with tag-set gc+heap+exit at debug level
- Set BiasedLockingStartupDelay to 0 instead of 4000ms
- Improvements for Docker Containers: modified JVM to be aware that it is running inside docker container. Linux only. Several JVM options available regarding CPU and RAM.
- org.ietf.jgss:krb5: Accept including .conf files in krb5.conf
- javac: New Class AST Node With enclosing Instance
- javac: Error Message When java.lang.IllegalAccessError Produced (when external tools have loaded javac classes with multiple classloaders)
- javadoc: Treating Failure to Access a URL as an Error instead of warning.
- javadoc: HTML Files in doc-files Subdirectories Wrapped with Standard javadoc Decorations.
- jshell: reduced time needed to start JShell.
- xml: XMLInputFactory.newFactory Incorrectly Deprecated in Java 9 and deprecation removed
- xml/jaxp: java.xml APIs With Raw Types were updated to add a type parameters