To run each example use: java --enable-preview --source 13 <FileName.java>

• Switch expressions improvements
  • Changed break from Java 12 to yield
• Text blocks
  • flag to compile: -Xlint:text-blocks
• API improvements
  • String methods:
    • stripIdent: same operation done by the compiler to strip incidental identation from text block';
    • translateEscapes: same operation done by the compiler to translate escapes in strings;
    • formatted: shortcut to String.format '"%s years old".formatted(42))
  • NIO improvements
• Socket and ServerSocket reimplementation (alignment to Project Loom)

• Creating Class-Data archives For AppCDS
  • flag to java -XX:ArchiveClassesAtExit=<FileHere.jsa> to generate class-data on exit
  • run with it: -XX:SharedArchiveFile=<FileHere.jsa>
• ZGC (Oracle's Z GC) returns unused memory to SO
  • -XX:ZUncommitDelay=<seconds> to set the delay in seconds
  • -XX:SoftMaxHeapSize: soft (won't generate OutOfMemoryError - will request more) limit to avoid the JVM to grow in memory

• 354 - Switch expression (preview 2)
• 355 - Text blocks (preview)
• 350 - Dynamic CDS Archives
• 351 - ZGC: Uncommit Unused Memory
• 353 - Reimplement the Legacy Socket API

• Tools
  • Maven: 3.5.0
    • compiler plugin: 3.8.0
    • surefire and failsafe: 2.22.0
    • plugins using ASM (e.g. the shade plugin) will likely need to be updated as well

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <release>13</release>
        <compilerArgs>
            --enable-preview
        </compilerArgs>
    </configuration>
</plugin>
<plugin>
    <artifactId>maven-surefire-plugin</artifactId>
    <configuration>
        <argLine>--enable-preview</argLine>
    </configuration>
</plugin>
<plugin>
    <artifactId>maven-failsafe-plugin</artifactId>
    <configuration>
        <argLine>--enable-preview</argLine>
    </configuration>
</plugin>

• Java 13 Documentation
• Java 13 Guide
• Switch Expression
• Text Block Guid