Cannot complile JOSM using Eclipse

[GerdP]

I don't know since when, but my Eclipse installation no longer worked. So I started with a fresh installation using
​https://www.eclipse.org/downloads/download.php?file=/technology/epp/downloads/release/2025-09/R/eclipse-java-2025-09-R-win32-x86_64.zip&mirror_id=1285
and an empty workspace.
I followed the steps described in the wiki https://josm.openstreetmap.de/wiki/DevelopersGuide/Compiling
After importing the project c:\josm\core the build is started automatically and ends with a popup showing

Errors occurred during the build.
Errors running builder 'Java Builder' on project 'josm'.
Internal Error compiling /josm/src/org/openstreetmap/josm/gui/widgets/PopupMenuButton.java

The log window shows two more problems.

The problem remains when I do "Maven -> Update Project... -> Select All -> OK"

[stoecker]

Internal error sounds much like a bug in eclipse or the toolchain.

Does it help to run maven once by hand. Maybe that skips the problematic file?

[GerdP]

Yes, it is probably an error in Eclipse. I tried with mvn compile. This is the log which looks similar to that produced with ant clean dist.
I didn't use maven before. How do I create the josm.jar without running all the unit tests?

c:\josm\core>mvn compile
[INFO] Scanning for projects...
[INFO]
[INFO] --------------------< org.openstreetmap.josm:josm >---------------------
[INFO] Building josm 1.5-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- enforcer:3.5.0:enforce (enforce-versions) @ josm ---
[INFO] Rule 0: org.apache.maven.enforcer.rules.version.RequireMavenVersion passed
[INFO] Rule 1: org.apache.maven.enforcer.rules.version.RequireJavaVersion passed
[INFO]
[INFO] --- checkstyle:3.5.0:check (validate) @ josm ---
[INFO] You have 0 Checkstyle violations.
[INFO]
[INFO] --- buildnumber:3.2.1:create (default) @ josm ---
[INFO] Get info from versioned directory: c:\josm\core
[INFO] Storing buildNumber: 19440 at timestamp: 1758005639100
[INFO] Get info from versioned directory: c:\josm\core
[INFO] Storing scmBranch: trunk
[INFO]
[INFO] --- dependency:3.7.0:properties (default) @ josm ---
[INFO]
[INFO] --- javacc:3.1.0:javacc (javacc) @ josm ---
Java Compiler Compiler Version 7.0.13 (Parser Generator)
(type "javacc" with no arguments for help)
Warning: Bad option value in "-JDK_VERSION=11" will be ignored.
Reading from file c:\josm\core\src\org\openstreetmap\josm\gui\mappaint\mapcss\MapCSSParser.jj . . .
Warning: Line 4, Column 3: Command line setting of "OUTPUT_DIRECTORY" modifies option value in file.
Note: UNICODE_INPUT option is specified. Please make sure you create the parser/lexer using a Reader with the correct character encoding.
File "TokenMgrError.java" does not exist.  Will create one.
File "ParseException.java" does not exist.  Will create one.
File "Token.java" does not exist.  Will create one.
File "SimpleCharStream.java" does not exist.  Will create one.
Parser generated with 0 errors and 1 warnings.
[INFO] Processed 1 grammar
[INFO]
[INFO] --- resources:3.3.1:copy-resources (copy-root-resources) @ josm ---
[INFO] Copying 2 resources from  to target\classes
[INFO]
[INFO] --- resources:3.3.1:resources (default-resources) @ josm ---
[INFO] Copying 1387 resources from resources to target\classes
[INFO] Copying 5 resources from  to target\classes
[INFO]
[INFO] --- compiler:3.13.0:compile (default-compile) @ josm ---
[INFO] Recompiling the module because of changed source code.
[INFO] Compiling 1890 source files with javac [debug release 11] to target\classes
[INFO] /c:/josm/core/src/org/openstreetmap/josm/actions/mapmode/MapMode.java: c:\josm\core\src\org\openstreetmap\josm\actions\mapmode\MapMode.java verwendet oder überschreibt eine veraltete API.
[INFO] /c:/josm/core/src/org/openstreetmap/josm/actions/mapmode/MapMode.java: Wiederholen Sie die Kompilierung mit -Xlint:deprecation, um Details zu erhalten.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  01:08 min
[INFO] Finished at: 2025-09-16T08:54:27+02:00
[INFO] ------------------------------------------------------------------------

[GerdP]

Forgot to answer the question: The mvn compile didn't help with the Eclipse problems.

[stoecker]

mvn package -DskipTests should do that.

[taylor.smock]

I also got the error

Internal compiler error: java.lang.RuntimeException: Internal Error compiling /josm/src/org/openstreetmap/josm/gui/widgets/PopupMenuButton.java at org.eclipse.jdt.internal.compiler.ProcessTaskManager.processing(ProcessTaskManager.java:139)

Eclipse doesn't even like opening the file.

I've done a little bit of debugging, and it doesn't like

      /**
       * Pass-through to {@link JButton#JButton()} allowing associated popup menu to be set
       * @param m the associated popup menu
       */
      public PopupMenuButton(JPopupMenu m) {
          super();
          this.initialize(m); // W: warning: [this-escape] possible 'this' escape before subclass is fully initialized
      }

More specifically, it doesn't like the {@link JButton#JButton()} bit. Removing the () "fixes" the issue.

Here is a diff, if you want to apply it:

src/org/openstreetmap/josm/gui/widgets/PopupMenuButton.java

@@ -72 +72 @@
     }
 
     /**
-     * Pass-through to {@link JButton#JButton()} allowing associated popup menu to be set
+     * Pass-through to {@link JButton#JButton} allowing associated popup menu to be set
      * @param m the associated popup menu
      */
     public PopupMenuButton(JPopupMenu m) {

I'm going to report a bug against Eclipse, if I can find the right place.

[GerdP]

Great. Many thanks, Taylor. I didn't even consider that the source itself could be the problem :O

[taylor.smock]

No problem.
I've just finished reporting the bug upstream (see ​https://github.com/eclipse-jdt/eclipse.jdt.core/issues/4401 ).

[GerdP]

My freshly installed Eclipse complains about these parameters:

                -javaagent:${com.ginsberg:junit5-system-exit:jar}
                -javaagent:${org.jmockit:jmockit:jar}

I guess I have to install additional software. Can you point me to the right locations?

[taylor.smock]

Eclipse should automatically replace the ${com.ginsberg.junit5-system-exit:jar} and ${org.jmockit:jmockit:jar} with the path to the jar (on Linux, ~/.m2/repository/com/ginsberg/junit5-system-exit/2.0.2/junit5-system-exit-2.0.2.jar and ~/.m2/repository/org/jmockit/jmockit/1.49.a/jmockit-1.49.a.jar).

[GerdP]

Well, I have those jar files but Eclipse doesn't replace anything. I get "Reference to undefined variable com.ginsberg".
I am pretty sure that this worked in the past, but it now also happens with the old eclipse installation, so I guess something in the new workspace folder is now missing. I didn't create a backup for that :(

For now, I replace the variables with fixed paths...

[GerdP]

In 19442/josm:

See #24467: Cannot complile JOSM using Eclipse

• fix javadoc error which causes internal error in Eclipse (patch by taylor.smock)