JMRI: Java Version-Specific Features
This page contains information about the compatibility and features of various Java versions. We use this information to decide on our road map for future JMRI versions. (For pre-Java-1.8 content, see the historical page.)
Note: The Java community is moving from a "few big Java releases, years apart" development cycle to a cycle with a new release every six months, and a long-term support (LTS) release every three years. (For background, see here, here, here). It's not yet clear what this will mean for JMRI's development and migration path. Much discussion is necessary.
As of February 2018, Oracle has scheduled end-of-life for Java 8 in January 2019, and intends to release the next Long Term Support version (notionally known as both Java 11 and Java 18.9) in September of 2018. Given that some users will need to move forward for other applications once Java 8 is End Of Life, at a minimum we'll have to have JMRI running under both Java 8 and Java 11/18.9 by January 2019. For more information on this, see also this Java Magazine article from November 2018 .
This section lists new Java capabilities, and which Java version they first appeared in. The "JDK" column shows the first Java Development Kit that could compile the feature; the "JRE" column lists the first runtime environment that could run the feature, including the needed JVM and library support.
|HiDPI graphics support for Windows and Linux users. Probably "just works" with JRE update, unless something in JMRI breaks on Java 9 on Windows (Currently support using very large fonts as a workaround, but it quickly breaks as text overlaps widget boundaries)||8||9|
|Multi-version JARs can help with migration, see discussion||9||9|
|The Deprecated annotation can take "since" and "forRemoval" specifications, which simplifies our API migration management a lot.||9||8|
|Java Platform Module System||9||9|
|UTF-8 Properties files (simplifies I18N)||9||9|
|Immutable Lists, Sets and Maps: More useful than it maybe sounds, because it can help keep the separate parts (i.e. better and worse code) of JMRI indepdendent.||9||9|
|JLink - improve packaging, faster startup||9||?|
|var syntax - improves readability of code, use of generics||10
|Even better support for immutable collections||10||?|
|It seems that MacOS X (macOS) users will lose the use of the OS X App menu for About, Preferences, and (critically) Quit handling on that platform||> 10||> 10|
|It seems that MacOS X (macOS) users will lose Applescript scripting||> 10||> 10|
|Improved String whitespace support||11||?|
|JMRI uses several com.sun classes that will, at some point, no longer be accessible. This was originally scheduled as part of JPMS for 1.9, but was later removed. At some point, we will need to migrate away from these before using a more advanced JRE or JDK.||> 11||> 11|
|The Z Garbage Collector may provide better performance because of reduced garbage collection pauses.||11||11|
|The Shenandoah garbage collector might be another source of better performance.||12||12|
|A standard installation of GraalVM is available that can run parts of Python 3.7. Although this is "far from complete", no other project appears to be emerging to include Python 3 support in i.e. Jython.||11||11|
This section lists the most recent Java Runtime version recommended by Oracle for various operating system versions. Please note that not all users of that operating system will have updated to this Java version; many will be using an older one.
JMRI development requires Java 8u101 or later. 8u101 contains a certificate change that's needed to link to some remote Javadocs.
Oracle's page on Java 1.7 requirements says "Note: As of April 8, 2014 Microsoft stopped supporting Windows XP and therefore it is no longer a supported platform." Google finds numerous pages that show how to install Java 1.7 on XP or XP SP2. Although the corresponding Java 8 page makes no mention of XP, it seems reasonable to assume the same applies. JMRI's Windows installation page keeps updated information on this. Several JMRI users have reported that Java 1.8_151 is the last one that can be cleanly installed and run on XP. See the Java download archive page for links to that.
As of April 18, 2018, the the Oracle Java 8 page was saying:
Public updates for Oracle Java SE 8 will remain available for individual, personal use through at least the end of 2020.
For more details, see the Java pages for:
- Java 8 (March 2014)
- Java 9 (Sept 2017) see also the OpenJDK page
- Java 10 (March 2018)
- Java 11 LTS (Sept 2018)
- Java 12 (March 2019)
- Java 13 (Sept 2019)
- Java 14 (March 2020)
- Java 15 (Sept 2020)
Java plans for end of life of various versions:
- Java 8 will keep receiving updates indefinitely for personal use. which 18-month warning expected when "indefinitely" ends. Note that Oracle is no longer actively maintaining Java 8. Commercial support for security patches ends in Spring 2020 for many organizations.
- Java 11, made available in September 2018, will be a "Long Term Support" (LTS) release. That means five years of support, through 2023.
- Java 9, 10, and 12 through 16 will not be LTS releases, and support will end shortly after the following release comes out.
- Java 17 is announced as the next LTS release, expected in September of 2021. It is also expected to get five years of support.
Java 11 only runs on 64-bit Windows versions (no 32-bit).
|OS and platform||Last JRE|
|Win 10 (64-bit)||10|
|Win 8 (32-bit)||8|
|Win 7 (32-bit)||8|
|Win Server 2008 (32-bit)||8|
|Win Web Server 2008 (32-bit)||1.6|
|Win 2000 (32-bit)||1.6|
|Win Server 2003 (32-bit)||1.6|
|Win 8 (64-bit)||10|
|Win Server 2012 (64-bit)||10|
|Win Server 2012 R2 (64-bit)||10|
|Win 7 (64-bit)||10|
|Win Server 2008 R2 (64-bit)||10|
|Win Server 2008 (64-bit)||1.7|
|Win Web Server 2008 R2 (64-bit)||1.6|
|Win Vista (64-bit)||10|
|Windows Vista (32-bit)||8
|Win 2003 (64-bit)||1.6|
|Windows 98 (2nd Ed)||1.5-11|
|Mac OS X 10.10 and later||10|
|Mac OS X 10.8.3||8|
|Mac OS X 10.7.3||1.7|
|Mac OS X 10.5.8||1.6 (Apple JVM)|
|Mac OS X 10.5.7 and earlier on Intel||1.5 (Apple JVM)|
|Mac OS X 10.3 and later on PowerPC||1.5 (Apple JVM)|
The following combination of JMRI - Java - Platform/OS versions was based on Oracle and OS developers sources. It's translated to the OS install instructions (follow hyperlink in OS headers):
|4.2||1.8||10.8.3+ Mountain Lion||Win7 SP1/8/10, Vista SP2, (XP)||5.5+||12.04+||14.04LTS|
|3.10.1||1.7||10.7.3 Lion||Win7 SP1/8/10, Vista SP2, (XP)||5.5+||12.04||12.04|
|3.10.1||1.6||10.6 Snow Leopard (JVM6)||Win2003, Win2000 (x86)||5.5||10.4||N/A|
|2.14.1||1.5||10.5.7 Leopard (JVM5)||Vista SP1, Win2000 SP3, Win8.x (x64)||9.04||N/A|
|2.8||1.5||10.4 Tiger||Win98 (2nd Ed), XP, ME||N/A|
|2.2||1.5||10.3 Panther||Win98, ME||N/A||N/A||N/A|
|1.3.1||10.3 Panther||Win95, Win98||N/A||N/A||N/A|
|1.6||1.1.8||MacOS9.1 (MRJ)||Win95, Win98||N/A||N/A||N/A|