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"Unknown constant pool type 19" during Java 9 build with module declaration [message #1774432]

Sat, 14 October 2017 09:30

ecl ecl

Messages: 9
Registered: October 2017

Junior Member

I created a simple Java 9 hello world application (an example is here https://github.com/CodeFX-org/demo-jpms-hello-world). Whenever I declare a module, the Java builder fails with the following message:

Quote:

Errors running builder 'Java Builder' on project 'demo-jpms-hello-world-master'.
Unknown constant pool type 19

Subsequent tries to run the hello world program naturally fail, the error message is as follows:

Quote:

Error occurred during initialization of boot layer
java.lang.module.FindException: Module org.codefx.demo.jpms_hello_world not found

Commenting out all content of module-info.java makes the builder and the program execution run as expected.

At the same time, compiling and running from the command line works as expected. Using the above hello world example, this is the code that works:

javac -d target/classes $(find src -name '*.java')

jar --create --file target/jpms-hello-world.jar --main-class org.codefx.demo.jpms.HelloModularWorld -C target/classes .

java --module-path target/jpms-hello-world.jar --module org.codefx.demo.jpms_hello_world

I am running Eclipse Oxygen.1a Release (4.7.1a) on Java 9+181.

As suggest by Eric Rizzo, this is a repost of https://www.eclipse.org/forums/index.php/t/1089414/.

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Re: "Unknown constant pool type 19" during Java 9 build with module declaration [message #1774441 is a reply to message #1774432]

Sat, 14 October 2017 13:26

Stephan Herrmann

Messages: 1853
Registered: July 2009

Senior Member

Quote:

Errors running builder 'Java Builder' on project 'demo-jpms-hello-world-master'.
Unknown constant pool type 19

Some plug-in invoked during the build is not Java 9-aware.

Please look up the exact version of plug-in org.eclipse.jdt.core.

Additionally, if there was an exception, the Error Log view should (hopefully) contain a corresponding stack trace (or look in .metadata/.log). What does it say?

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Re: "Unknown constant pool type 19" during Java 9 build with module declaration [message #1774461 is a reply to message #1774432]

Sun, 15 October 2017 15:46

ecl ecl

Messages: 9
Registered: October 2017

Junior Member

Thank you very much for the plug-in hint.

I was using Lombok, not in this particular project, but in eclipse. Removing it solved the problem (apparently, Lombok has no eclipse support for Java 9 yet).

For anybody else searching for a troublesome plug-in: I did not find any information in the Error Log view or .metadata/.log, but starting eclipse from command line revealed the stack trace.

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