Setting the debug option to false still compiles the code with line numbers resulting in increased class file.

When I compile with -Dmaven.compiler.debug=true I do get a reduction in size however compiled code is still 10-20% larger than that compiled by either ant with debug=false or javac with the '-g:none' option.

Here's a closer look at the same class extracted from jars created with maven and ant using debug-false:

$ javap -l -verbose -c org/concord/mw2d/ActionStateEvent

The maven-generated class had three constants not in the ant-generated class:

const #12 = Asciz	LineNumberTable;
const #16 = Asciz	SourceFile;
const #17 = Asciz	ActionStateEvent.java;

In addition each method in the class had a LineNumberTable like this:

LineNumberTable:
 line 30: 0
 line 31: 5
 line 32: 10
 line 33: 15

It seems the only way to get maven to compile without the debugging resources is to add 'g:none' as a compiler argument for javac ... and this doesn't work from the command line – it only works if it is in the configuration element for the maven-compiler-plugin in the pom like this:

<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-compiler-plugin</artifactId>
      <configuration>
        <compilerArgument>-g:none</compilerArgument>
        <source>1.5</source>
        <target>1.5</target>
      </configuration>
    </plugin>
  </plugins>
</build>

If the compilerArgument to 'g:none' is not set in the pom I can't get any variation of the following command line arguments to compile without some debugging info.

with or without:

maven.compiler.debug=false

with or without any of the following:

maven.compiler.compilerArgument=g:none
maven.compiler.compilerArgument='g:none'
maven.compiler.compilerArguments=g:none
maven.compiler.compilerArgument='g:none'

But I'd like the default to include debugging resources and to be able to easily optionally package without the debug resources – the easiest way would be able to pass in a command line argument ...

The forensics on the maven-generated version of the class files above was generated with v2.0.2 of the compiler plugin.

In that example (where there was a partial reduction in compiled class size) I was passing in the debug=false parameter on the command line:

$ mvn clean; mvn -Dmaven.compiler.debug=true

I just tried with v2.3.2 of the compiler plugin and running the same command from a shell now produces compiled code with all the additional debug resources.

Setting <compilerArgument>-g:none</compilerArgument> still results in compilation without adding debug resources when using v2.3.2 of the compiler plugin

Ahh ... also setting the debuglevel=none parameter is the solution:

The examples below refer to a jar I am building: mw.jar with a nominal size of 7.2 MB

mvn -Dmaven.compiler.debug=true -Dmaven.compiler.debuglevel=none

results in an mw.jar that is just 5.4 MB.

So ... the logic is:

During a regular mvn compile maven.compiler.debug is true and the debug resources are added... so far so good, that makes stacktraces useful.

mw.jar => 7.2 MB

Setting maven.compiler.debug to false makes the compiled code smaller ... but some debug stuff is still there:

mw.jar => 6.3 MB

Setting maven.compiler.debuglevel to 'none' results in the smallest code size:

mw.jar => 5.4 MB

But only if maven.compiler.debug is also set to true! If maven.compiler.debug is false and maven.compiler.debuglevel is none:

mw.jar => 6.3 MB

http://maven.apache.org/plugins/maven-compiler-plugin/compile-mojo.html#debuglevel

Keyword list to be appended to the -g command-line switch.
Legal values are none or a comma-separated list of the
following keywords: lines, vars, and source. If debuglevel is
not specified, by default, nothing will be appended to -g. If
debug is not turned on, this attribute will be ignored.

Maven is special ...

I just tried the debug=true, debuglevel=none approach. As near as I can tell the line number table is STILL in the class file.

David, Which versions of the compiler plugin are you using?

I was using v2.3.2 in my tests above.

...
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-compiler-plugin</artifactId>
  <version>2.3.2</version>

@Stephen - I was using 2.0.2. Apparently that is what Maven 2.2.1 uses by default.

When I switch to 2.3.2 I could replicate your behavior exactly. Apparently v2.0.2 quietly ignores the <debuglevel> configuration option.