"Error running javac.exe compiler" when using ant to compile Eclipse plugin

Question

Hi
I encounter an error "Error running C:\jdk1.5.0_06\bin\javac.exe compiler" when building my project using ant1.7.
My project has 10 eclipse plugins, and each plugin is compiled by invoking following ant target
<!-- ===================================================================
Compile specified plugin
     target parameters:
          param.plugin.dir: the plugin directory
          param.plugin.targetJarFile: the name of jar file for the given plugin
          param.plugin.src.dir: the folder name of source codes. Note: it is relative path name
          param.fork: indicate if another process is forked to run javac
=================================================================== -->
<target name="compilePlugin">
     <!-- Prepare compile environment -->
     <!-- Delete obsolete build folder -->
     <delete dir="${param.plugin.dir}/${build.dir}" quiet="true"/>
     <!-- Delete obsolete jar file -->
     <delete file="${param.plugin.dir}/${param.plugin.targetJarFile}" quiet="true"/>
     <mkdir dir="${param.plugin.dir}/${build.dir}"/>
     <!-- Compile source codes -->
     <javac      srcdir="${param.plugin.dir}/${param.plugin.src.dir}"
               destdir="${param.plugin.dir}/${build.dir}"
               failonerror="${javacFailOnError}"
               verbose="${javacVerbose}"
               debug="${javacDebugInfo}"
               deprecation="${javacDeprecation}"
          optimize="${javacOptimize}"
               source="${javacSource}"
               target="${javacTarget}"     
               fork="${param.fork}" memoryInitialSize="256m" memoryMaximumSize="512m">
          <classpath refid="compile.classpath" />
     </javac>
     <!-- Create plugin jar file -->
     <copy todir="${param.plugin.dir}/${build.dir}" failonerror="true">
          <fileset dir="${param.plugin.dir}/${param.plugin.src.dir}" excludes="**/*.java, **/package.htm*" />
     </copy>
     <jar jarfile="${param.plugin.dir}/${param.plugin.targetJarFile}" basedir="${param.plugin.dir}/${build.dir}"/>
     <delete dir="${param.plugin.dir}/${build.dir}" quiet="true"/>
</target>
Since each of first 9 plugins contains less than 500 java source files, we always set "param.fork" to false when invoking this ant target.
For the 10th plugin, it has about 1000 source files. If we set "param.fork" to false, we will get the error "Error running javac.exe compiler". So we have to set "param.fork" to true when compiling it. This week, this plugin contains about 1250 files and we get the same error again when compiling it. I tried to increase the "memoryMaximumSize" to "768", but still couldn't get through it.
BTW, There are about 150 jar files in our classpath for compiling plugins. Do many jar files cause this problem?
Any help is highly appreciated.
Many thanks
Oceanman

Answer 1

I encountered a very similar error and I was able to resolve it by removing the following parameters from the javac task:
fork="${param.fork}"
memoryInitialSize="256m"
memoryMaximumSize="512m"My values were not the same as yours, before I removed them, the values were set to:
fork="true"
memoryInitialSize="256m"
memoryMaximumSize="256m" Not sure why this fixed my problem but it did. I was using Ant 1.7 and Java 1.6_07 hope this helps.