Build tips

Tips for resolving build problems

Some typical issues encountered when building PL/Java can be listed here, along with tips for resolving them.

The tips that always apply

Please do carefully read the build instructions, especially the "software prerequisites" section, and the "special topics" section for any that apply to the platform where you are building.

Also be sure to review the "troubleshooting the build" section at the end of the build instructions page.

If you review the mailing list archive and the issues list, you may find a report of a situation like your own. (On the issues list, it is possible someone reported an issue, a solution was found, and the issue was closed, so look at recent closed issues too.)

Failure shown for pljava-api

Fatal error compiling caused by invalid flag: --release

By itself, Fatal error compiling isn't very helpful. Use Maven's -e option to get full exception stack traces.

org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal ...:compile (default-compile) on project pljava-api: Fatal error compiling
...
Caused by: org.apache.maven.plugin.MojoExecutionException: Fatal error compiling
...
Caused by: org.codehaus.plexus.compiler.CompilerException: invalid flag: --release
...
Caused by: java.lang.IllegalArgumentException: invalid flag: --release
    at com.sun.tools.javac.api.JavacTool.processOptions
    ...
    at org.codehaus.plexus.compiler.javac.JavaxToolsCompiler.compileInProcess

If you see a stack trace like this building the PL/Java 1.6 series or later, you simply have Maven running on a Java version that is too old. PL/Java 1.6.x requires Java 9 or later.

It can be possible to have the environment set up so that simple command

javac --version

at the shell will find the javac that you want on the PATH and report that version, but the mvn command finds a different installed Java version and uses it to run Maven. Because Maven does Java compilation in-process, the PL/Java code ends up being compiled by whatever Java version is running Maven itself. If that version is not at least Java 9, this error results. The command

mvn --version

is useful because it does not show only the version of Maven, but also the version of Java that Maven has found to run with.

The JAVA_HOME variable can be set in the environment to ensure Maven runs on the needed version of Java.

Failure shown for pljava-so

Missing -devel prerequisite packages

The most common cause of reported failures building pljava-so is a missing required file. Sometimes your distribution's packaging system will have chosen to organize a prerequisite piece of software into more than one package, for example, one that contains only library files, and another with a name ending in -dev or -devel that contains the necessary .h files. Some distributions take this further than others; see the "special topics" section for Ubuntu for an example where even libraries built as part of PostgreSQL itself are split up into multiple separate packages.

The solution is simple: look over the error messages from the pljava-so section of the build output to find any that refer to a file that could not be found. Usually it will be a .h file or a library (.so, .dll, .dylib, etc.).

Find out the name of the package, according to the OS or package distribution you are using, that contains the missing file, install that package, and you have probably solved the whole problem.

Further tip: Finding the error message that really mattered is easier if you follow the "troubleshooting the build" tip about the -Pwnosign option, to cut down the number of other messages that do not matter, if that option works on your platform.

Still stuck?

Please describe the issue you are facing on the mailing list.