diff --git a/build.xml b/build.xml
index 171050cc3a..1222236b89 100644
--- a/build.xml
+++ b/build.xml
@@ -359,7 +359,7 @@
         windowtitle="${ant.project.name} API" classpathref="cassandra.classpath"
         bottom="Copyright © 2009- The Apache Software Foundation"
         useexternalfile="yes" encoding="UTF-8" failonerror="false"
-        maxmemory="256m" additionalparam="${jdk11-javadoc-exports}">
+        maxmemory="1024m" additionalparam="${jdk11-javadoc-exports}">
         <filesets/>
       </javadoc>
       <fail message="javadoc failed">