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 intendeds 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 EOL, at a minimum we'll have to have JMRI running under both Java 8 and Java 11/18.9 by January 2019.
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|
|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||9||9|
|It seems that MacOS X (macOS) users will lose Applescript scripting||9||9|
|Multi-version JARs can help with migration, see discussion||...||9|
|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.||?||?|
|Java Platform Module System||1.9||1.9|
|JUTF-8 Properties files (simplifies I18N)||1.9||1.9|
|JImmutable 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.||1.9||1.9|
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.
Oracle's page on Java 1.7 requirements which 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. JMRI's Windows installation page will have updated information on this.
Last updated February 10, 2018. At that time, although Java 9 was available, it was not being recommended for any platform. The situation may become clearer after the next Java release(s) are shipped, perhaps March or September 2018.
|OS and platform||Last JRE|
|Win 8 (32-bit)||1.8|
|Win 7 (32-bit)||1.8|
|Win Server 2008 (32-bit)||1.8|
|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)||1.8|
|Win Server 2012 (64-bit)||1.8|
|Win Server 2012 R2 (64-bit)||1.8|
|Win 7 (64-bit)||1.8|
|Win Server 2008 R2 (64-bit)||1.8|
|Win Server 2008 (64-bit)||1.7|
|Win Web Server 2008 R2 (64-bit)||1.6|
|Win Vista (64-bit)||1.8|
|Windows Vista (32-bit)||1.8
|Win 2003 (64-bit)||1.6|
|Windows 98 (2nd Ed)||1.5-11|
|Mac OS X 10.8.3 and later on Intel||1.8|
|Mac OS X 10.7.3 and later on Intel||1.7|
|Mac OS X 10.5.8 and later on Intel||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|