diff --git a/java-extension/pom.xml b/java-extension/pom.xml
index 6ca784e4..f65820f6 100644
--- a/java-extension/pom.xml
+++ b/java-extension/pom.xml
@@ -95,13 +95,4 @@
             </plugin>
         </plugins>
     </build>
-    <repositories>
-        <repository>
-            <id>oss.sonatype.org</id>
-            <url>https://oss.sonatype.org/content/repositories/snapshots/</url>
-            <snapshots>
-                <enabled>true</enabled>
-            </snapshots>
-        </repository>
-    </repositories>
 </project>
diff --git a/scripts/buildJdtlsExt.js b/scripts/buildJdtlsExt.js
index 8bcce4c2..2f36c1c1 100644
--- a/scripts/buildJdtlsExt.js
+++ b/scripts/buildJdtlsExt.js
@@ -38,7 +38,10 @@ const bundleList = [
 // Set MAVEN_OPTS to disable XML entity size limits for JDK XML parser
 const env = { ...process.env };
 env.MAVEN_OPTS = (env.MAVEN_OPTS || '') + ' -Djdk.xml.maxGeneralEntitySizeLimit=0 -Djdk.xml.totalEntitySizeLimit=0 -DentityExpansionLimit=0';
-cp.execSync(`${mvnw()} clean verify`, { cwd: serverDir, stdio: [0, 1, 2], env });
+// `eclipse.p2.mirrors=false` stops p2 from following download.eclipse.org's mirror
+// redirect, which hands out a different third party host per request and makes the
+// set of addresses the build contacts impossible to express as an allow list.
+cp.execSync(`${mvnw()} clean verify -Declipse.p2.mirrors=false`, { cwd: serverDir, stdio: [0, 1, 2], env });
 copy(path.join(serverDir, 'com.microsoft.java.test.plugin/target'), path.resolve('server'), (file) => path.extname(file) === '.jar');
 copy(path.join(serverDir, 'com.microsoft.java.test.runner/target'), path.resolve('server'), (file) => file.endsWith('jar-with-dependencies.jar'));
 copy(path.join(serverDir, 'com.microsoft.java.test.plugin.site/target/repository/plugins'), path.resolve('server'), (file) => {