Title: Moving Java Forward Faster
Speakers: Donald Smith
See my live blog table of contents from Oracle Cloud
New Java Release Model
- “no more limos; think trains”
- From Java 2 to Java 8, had target release of every two years. Slipped a bunch of times (once to 5 years)
- From Java 2 to Java 8, did update releases roughly every 6 months. (not counting security releases). These update releases had new APIs or functionality. Ex: 8u20, 8u40, 8u60
- Java 9 was released in September 2017 and is already at end of life
- Tried to make case that Java 10 is really 9.1 and Java 12 is really 10.1 and Java 13 is really 10.2 and so forth. [I don’t think this analogy holds. Talking to Mark Reinhold suggests that they aren’t trying to make major changes specifically for 11).
- Didn’t use 9.1, 10.1, etc because need major version number to make spec change.
- Carve up changes across releases instead of a major release every few years.
- Every six months is now a feature release and can potentially change the spec.
- Enterprises do not like 6 month releases so every 3 years is LTS release.
- Java 11 is 18.9 LTS. So the LTS still uses the yy.m naming convention. So Java 17 will be the 21.9 LTS. If so java –version get vendor string that will have both Java 11 and 18.9 in string for Oracle JDK
- Java 11 (18.9 LTS) will be supported for about 5 years plus 3 years of extended support.
- LTS releases will be more stable because people are using the interim releases who don’t care about LTS.
- Java 6 support ends in late 2018. Java 7 support ends in 2022 and Java 8 ends in 2025. Java 8 might be supported longer. TBD.
- Oracle will be producing Open JDK binaries vs it being a third party thing. Open JDK binaries are GPL licensed. They will only be available for 6 months for Java 11, 17, etc
- Open sourcing the commercial features that are part of the JDK – mission control, flight recorder, app class data sharing, java usage tracker (see how many JREs used in system).
- Separately packaged tools will stay commercial
What’s new in Java 9
- Last “major” release. 100+ features
- No longer using word “major” because releases are frequent and incremental.
- Jigsaw gives smaller footprint to attack by having less modules.
- java misc Unsafe – [the usual so not writing it up]
- AOT compiler – for application as well. Not immediate, but coming.
- jshell – live demo
- G1 is now default garbage collector
Long term goal of jlink
- Horror stories where people need a dozen versions of JREs because apps don’t work with various patches.
- Long term goal – shift thinking of how package apps from standalone JRE to shipping a JRE with the app itself. (for client side apps for users)
- Gut: This makes the problem worse
- jlink lets you create custom runtime optimized for program. Doesn’t have all the modules.
- Get smaller package with just what need.
- [security implications are interesting; have to patch each app but apps far less likely to contain vulnerability]
- jlink also requires packing for hardware
- Goal shifting to jlink because browsers and OS are heading away from one common Java for Windows and Mac. Worried that one day there will be an OS update that will block separate JRE.
- [I asked why it isn’t a problem for developers if OS blocks common java. He said maybe a configuration or a developer build. So power users vs end users problem]
What’s new in Java 10
- First feature release (vs major release)
- Type inference – var x – … (example of a feature that couldn’t be in an update release since changes Java spec)
- G1 garbage collector uses multiple threads
- 12 JEPs (Java Enhancement Proposals) targeted.
- Open source root certificates. Can connect to many TLS servers out of the box. Vs OpenJDK for RHEL which assumes you have Firefox installed.
What’s new in Java 11
- 4 JEPs already targeted. Waiting until ready to target
- Removing some APIs
Future – version not yet known
- Optimize for data; not just code. So big data libraries don’t need to call native code
- Project Panama – interoperate with native libraries (better JNI)
- Project Loom – lightweight threads
- Project Valhalla – value types. Maybe Java 12?
Excellent session. I thought I understood the release model and still learned some nuances! Glad he spent more than half the session on this topic. And I hadn’t realized the long term implications for Jigsaw/jlink.