For reasons not worth going into, we are still running our project code under Java 1.5, and this has caused no end of interesting scenarios, including today's issue when attempting to run a unit test in debug mode. I received the following error in Compile Messages in IntelliJ (v9, also an involved story):
Information:Usage: javac Information:where possible options include: Information: -g Generate all debugging info Information: -g:none Generate no debugging info Information: -g:{lines,vars,source} Generate only some debugging info Information: -verbose Output messages about what the compiler is doing Information: -deprecation Output source locations where deprecated APIs are used Information: -classpath Specify where to find user class files Information: -cp Specify where to find user class files Information: -sourcepath Specify where to find input source files Information: -bootclasspath Override location of bootstrap class files Information: -extdirs Override location of installed extensions Information: -endorseddirs Override location of endorsed standards path Information: -d Specify where to place generated class files Information: -encoding Specify character encoding used by source files Information: -source Provide source compatibility with specified release Information: -target Generate class files for specific VM version Information: -version Version information Information: -help Print a synopsis of standard options Information: -X Print a synopsis of nonstandard options Information: -J Pass directly to the runtime system Information:Compilation completed with 1 error and 0 warnings Information:1 error Information:0 warnings Error:javac: invalid target release: 1.6
I googled the last line of this and got a bunch of recommendations regarding pointing JAVA_HOME at Java 1.6, but because of our constraint that solution is not for us. Also, there was no mismatch between the Java version being used by IntelliJ and that being used by Maven (you can do mvn -version to check).
Finally I discovered that IntelliJ has a hidden little default setting in the compiler that was effing it up. I discovered it via the Maven tab -> properties, but it's just a project setting. I used the top left search field to search for Java. That gives several results, including one for the Java Compiler:
As you can see, there's this secret little config that is the cause of the problem:
Additional command line parameters: -target 1.6
DERP!
When I removed this parameter and reran my debug unit test, everything worked just fine.
As you can see, there's this secret little config that is the cause of the problem: