diff --git a/core/combo/javac.mk b/core/combo/javac.mk
index 99bd0ee..5c2668c 100644
--- a/core/combo/javac.mk
+++ b/core/combo/javac.mk
@@ -35,7 +35,7 @@
 endif
 
 # Whatever compiler is on this system.
-COMMON_JAVAC := $(JAVACC) -J-Xmx1024M $(common_jdk_flags)
+COMMON_JAVAC := $(JAVACC) -J-Xmx2048M $(common_jdk_flags)
 
 # Eclipse.
 ifeq ($(CUSTOM_JAVA_COMPILER), eclipse)