diff --git a/build.xml b/build.xml
index b46c50491f..fa4276d550 100644
--- a/build.xml
+++ b/build.xml
@@ -367,7 +367,7 @@
         windowtitle="${ant.project.name} API" classpathref="cassandra.classpath"
         bottom="Copyright © 2009- The Apache Software Foundation"
         useexternalfile="yes" encoding="UTF-8" failonerror="false"
-        maxmemory="256m" additionalparam="${jdk11plus-javac-exports}">
+        maxmemory="1024m" additionalparam="${jdk11plus-javac-exports}">
         <filesets/>
       </javadoc>
       <fail message="javadoc failed">