diff --git a/build.xml b/build.xml
index e56d8badd7..fb30ef5d4e 100644
--- a/build.xml
+++ b/build.xml
@@ -393,7 +393,7 @@
           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">