diff --git a/build.xml b/build.xml
index 4aff403372ac232a965610728fb4426c4d7180d4..8583d6d1019b678d495bf0e7b7a822c5806e83fa 100644
--- a/build.xml
+++ b/build.xml
@@ -113,6 +113,9 @@
   <!-- Compiles the source directory -->
   <target name="compile" depends="init,compile-idl,prepare-src">
     <javac
+      fork="true"
+      memoryinitialsize="256m"
+      memorymaximumsize="256m"
       srcdir="${build.src.main}"
       destdir="${build.dest.main}"
       excludes="nsdb/**,seqdb/**,type/**,lib/**,src/**,uk/ac/sanger/artemis/components/MacHandler.java,uk/ac/sanger/artemis/components/filetree/FileTree.java,uk/ac/sanger/artemis/components/filetree/SshFileTree.java,uk/ac/sanger/artemis/ExternalProgramUtils.java"