Java 12

    switch (day) {
        case MONDAY, FRIDAY, SUNDAY -> System.out.println(6);
        case TUESDAY                -> System.out.println(7);
        case THURSDAY, SATURDAY     -> System.out.println(8);
        case WEDNESDAY              -> System.out.println(9);
    }

Re: Java 12

#6

Post by azhenley » Tue, Mar 19, 2019, 9:07 PM UTC

The most interesting new feature I think is the Shenandoah GC. The summary from [1]:

"Add a new garbage collection (GC) algorithm named Shenandoah which reduces GC pause times by doing evacuation work concurrently with the running Java threads. Pause times with Shenandoah are independent of heap size, meaning you will have the same consistent pause times whether your heap is 200 MB or 200 GB."

The original algorithm was published in 2016 [2]. It consists of 4 phases: initial marking, concurrent marking, final marking, and concurrent compaction.

[1] http://openjdk.java.net/jeps/189

[2] https://dl.acm.org/citation.cfm?id=2972210

Re: Java 12

#7

Post by jason0597 » Tue, Mar 19, 2019, 9:08 PM UTC

azhenley wrote: post #5

connorlwilkes wrote: post #3

The new switch feature looks nice, the way it previously used to work was so unwieldy.

In case someone is curious what it looks like with the new -> form: switch (day) { case MONDAY, FRIDAY, SUNDAY -> System.out.println(6); case TUESDAY -> System.out.println(7); case THURSDAY, SATURDAY -> System.out.println(8); case WEDNESDAY -> System.out.println(9); }

Reminds me of Kotlin's "when" statement

Re: Java 12

#8

Post by _old_dude_ » Tue, Mar 19, 2019, 9:11 PM UTC

azhenley wrote: post #5

connorlwilkes wrote: post #3

The new switch feature looks nice, the way it previously used to work was so unwieldy.

In case someone is curious what it looks like with the new -> form: switch (day) { case MONDAY, FRIDAY, SUNDAY -> System.out.println(6); case TUESDAY -> System.out.println(7); case THURSDAY, SATURDAY -> System.out.println(8); case WEDNESDAY -> System.out.println(9); }

or using the switch as an expression

  System.out.println(switch(day) {
    case MONDAY, FRIDAY, SUNDAY -> 6;
    case TUESDAY                -> 7;
    case THURSDAY, SATURDAY     -> 8;
    case WEDNESDAY              -> 9;
    });

Re: Java 12

#9

Post by paulddraper » Tue, Mar 19, 2019, 9:11 PM UTC

crooked-v wrote: post #4

Still nothing to handle checked exceptions in streams properly... sigh.

I share the conclusion of the other statically typed JVM languages (Scala, Kotlin): checked exceptions are bad.

Re: Java 12

#10

Post by darksaints » Tue, Mar 19, 2019, 9:15 PM UTC

Anybody know how the graal project ties in with all of this? Is oracle effectively developing 3 different JVMs (OpenJDK, Oracle JDK, GraalVM)? Or is there some sort of convergence plan?

From what I understand, graal has made a lot of headway with language interop, as well as a handful of specific memory optimizations and native compilation, but overall is lagging in pure throughput/latency performance behind hotspot. It would be really cool if we could get the best of both worlds.