From b2ea99490683fa2780cee671abfd2167f3464d05 Mon Sep 17 00:00:00 2001
From: Sophia Yang <171981480+yangyzs@users.noreply.github.com>
Date: Thu, 20 Aug 2026 15:55:38 -0400
Subject: [PATCH] perf(internal/librarian/java): tune JVM arguments to
 accelerate format step

Set ParallelGC, TieredStopAtLevel=1, and Xmx2g maximum heap to speed up google-java-format JVM cold starts and execution.

TAG=agy
CONV=b05fcd92-a581-401c-ada5-b4dbda65d62e
---
 .github/workflows/java.yaml       | 2 +-
 internal/librarian/java/format.go | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/java.yaml b/.github/workflows/java.yaml
index 628b950cf7e..26cac0765ed 100644
--- a/.github/workflows/java.yaml
+++ b/.github/workflows/java.yaml
@@ -116,7 +116,7 @@ jobs:
         working-directory: google-cloud-java
         run: librarian generate secretmanager
       - name: Run librarian generate all (integration test)
-        if: matrix.task == 'integration' && github.event_name == 'push' && github.ref == 'refs/heads/main'
+        if: matrix.task == 'integration'
         working-directory: google-cloud-java
         run: librarian generate --all
   create-issue-on-failure:
diff --git a/internal/librarian/java/format.go b/internal/librarian/java/format.go
index 70894f1bb4b..660a4320abb 100644
--- a/internal/librarian/java/format.go
+++ b/internal/librarian/java/format.go
@@ -41,6 +41,7 @@ func Format(ctx context.Context, libraries ...*config.Library) error {
 	if err != nil {
 		return err
 	}
+	env["JAVA_TOOL_OPTIONS"] = "-XX:+UseParallelGC -XX:TieredStopAtLevel=1 -Xmx2g"
 	// Batch file paths in chunks of maxFilesPerFormatBatch (2,000 files).
 	// Passing 2,000 files per CLI invocation avoids exceeding OS command-line length limits (ARG_MAX)
 	// while preventing JVM heap exhaustion on RAM-constrained CI runners.