Travis CI为什么认为我的代码是Java 1.3，以及如何解决它？

Question

I'm trying out Travis CI with a Java project (pretty standard Maven, Spring setup).

Based on Travis docs, this should suffice in the .travis.yml file:

language: java

Travis should notice the project's pom.xml and run mvn test by default.

However, the Travis build fails, giving me:

error: static import declarations are not supported in -source 1.3

My sources are Java 1.6. How and where should I tell that to Travis? The Java project docs don't mention -source option at all. (Also, 1.3 is a bit strange default, isn't it?)

Answer 1

Got it working by customising install and script in .travis.yml like this:

language: java
install: mvn install -Dmaven.compiler.target=1.6 -Dmaven.compiler.source=1.6 -DskipTests=true
script: mvn test -Dmaven.compiler.target=1.6 -Dmaven.compiler.source=1.6

...as suggested in this answer .

Anyway, I don't know where exactly the Java 1.3 default comes from, but IMHO that should be fixed. Travis documentation talks of "reasonably good defaults" , but in this case that doesn't seem to be true.

Another option would be to add a lengthy piece of Maven XML to explicitly specify the source & target levels. Well, personally I'm opposed to the idea of having to do that, just because a CI environment has silly defaults. (Isn't the whole point with Maven to avoid explicitly specifying stuff by using reasonable conventions?) With my current pom.xml everything works fine locally (eg mvn test ) as well as when deploying on Heroku.

Update (2015, Java 8)

Just wanted to add that as of 2015, with a Java 8 codebase, you no longer need such customisations in Maven or Travis config. You get away with the following:

In pom.xml , under top-level <project> :

<properties>
    <java.version>1.8</java.version>
</properties>

And in .travis.yml :

language: java
jdk: oraclejdk8 

Which is nice. Note that JDK 8 must be specified, even when pom.xml sets Java version to 1.8. Travis otherwise defaults to JDK 7.

Answer 2

This is because you do not explicit set the source and target levels in your maven-compiler-plugin configuration in your pom.xml.

Older versions of Maven then use the javac default which is Java 1.3 in OpenJDK (as opposed to 1.5 in Oracle Java).

Answer 3

This problem is certainly related to a Bug in Maven3 Ubuntu package , which is currently installed on Travis worker machines.

Good News: In next Travis CI build environment, Maven 3.1.1 will be installed with Apache tarball release . This update is planned to be deployed in November 2013...