Details
- Type:
Bug
- Status: Closed
- Priority:
Major
- Resolution: Won't Fix
- Affects Version/s: 2.1
- Fix Version/s: None
- Labels:None
- Environment:Windows XP Professional Version 5.1.2600 Service Pack 3 Build 2600, Dell OptiPlex GX280, Total Physical Memory 4,096.00 MB
Description
Given the following example:
public class Main { public static void main(String[] args) { for (StackTraceElement stackTraceElement : Thread.currentThread().getStackTrace()) System.out.println(stackTraceElement); } }
and pom.xml
<project xmlns="" xmlns: <modelVersion>4.0.0</modelVersion> <groupId>com.greg</groupId> <artifactId>TestApp</artifactId> <version>1</version> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <debug>none</debug> <source>1.5</source> <target>1.5</target> </configuration> </plugin> </plugins> </build> </project>
after compiling and running we get:
{TestApp}\target\classes>dir Main.class 05/02/2010 XX:XX 564 Main.class {TestApp}\target\classes>java -cp . Main java.lang.Thread.dumpThreads(Native Method) java.lang.Thread.getStackTrace(Thread.java:1383) Main.main(Main.java:3)
NOTE !!!: the number of line (Main.java:3) has been shown
However when you compile the same java code using the javac we get:
{TestApp}\src\main\java>javac -g:none -source 1.5 -target 1.5 Main.java {TestApp}\src\main\java>dir Main.class 05/02/2010 XX:XX 477 Main.class {TestApp}\src\main\java>java -cp . Main java.lang.Thread.dumpThreads(Native Method) java.lang.Thread.getStackTrace(Thread.java:1383) Main.main(Unknown Source)
NOTE !!!: the number of line has not been shown
Please find the whole sample project in Eclipse that uses m2eclipse plugin, that is configured for using external maven 2.2.1
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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
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.
Please refer to if you're wondering why this issue was closed out.
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:
The maven-generated class had three constants not in the ant-generated class:
In addition each method in the class had a LineNumberTable like this:
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:
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:
with or without any of the following:
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 ...