Java 10 support?

[aclowkey]

Description of the issue:
Running a Java10 compiled, jib built image fails:

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: c/z/o/App has been compiled by a more recent version of the Java Runtime (class file version 54.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:495)

Expected behavior:
App should run?
Steps to reproduce:
Compile with java10
Environment:
Maven

[chanseokoh]

Jib uses gcr.io/distroless/java as the base image by default, which uses openjdk8. For Java 10, I think you should find a reliable base image with Java 10, and configure Jib to use it (pom.xml).

[coollog]

+1 @chanseokoh

For example, you could try using openjdk:10-jre as your from image.

[aclowkey]

@coollog I tried that and it failed as unauthorized. Do I need credentials for the public image?
{"errors":[{"code":"UNAUTHORIZED","message":"authentication required","detail":[{"Type":"repository","Class":"","Name":"library/openjdk","Action":"pull"}]}]}

[coollog]

@aclowkey We are cutting a release of version 0.9.4 soon with a fix for that issue (#549)

[patflynn]

@coollog should we file a FR against distroless/java for more up-to-date java support? Jib should be able to pick the right base-image based off of the maven/gradle java config.

[briandealwis]

GoogleContainerTools/distroless#214

[briandealwis]

GoogleContainerTools/distroless#173

[briandealwis]

I suppose we could hard-code a check that if a <from> image isn't specified then we check the maven compiler settings. Or better yet, use the Maven compiler settings to determine the <from> image when not specified.

[coollog]

@aclowkey Can you try again with version 0.9.4?

[aclowkey]

@coollog Works! Image size is 200Mb more tho. Default produces an image size of 77Mb, with JDK10 it comes out as ~270Mb

[coollog]

@aclowkey Yea, openjdk images tend to be larger than distroless. Did you try using openjdk:10-jre-slim? It's a lot smaller than openjdk:10-jre (286MB vs 632MB).

[aclowkey]

@coollog Much better! ~130Mb

[briandealwis]

Doesn't really make sense to address this until we have blessed images for other JRE versions.

[coollog]

We will skip Java 10 and add support for detection and use of LTS Java 11 version of gcr.io/distroless/java once it is available.

[chanseokoh]

Java 11 Distroless is available, and Jib uses it by default for Java 9+ apps. (#1279, #1510).