Increase javac heap to 4096M

Bug: 246361502
Test: TH
Change-Id: I787871a8fe924857cde550700acd15682b924b8b
diff --git a/java/config/config.go b/java/config/config.go
index b026d73..03288fe 100644
--- a/java/config/config.go
+++ b/java/config/config.go
@@ -78,7 +78,7 @@
 func init() {
 	pctx.Import("github.com/google/blueprint/bootstrap")
 
-	exportedVars.ExportStringStaticVariable("JavacHeapSize", "2048M")
+	exportedVars.ExportStringStaticVariable("JavacHeapSize", "4096M")
 	exportedVars.ExportStringStaticVariable("JavacHeapFlags", "-J-Xmx${JavacHeapSize}")
 
 	// ErrorProne can use significantly more memory than javac alone, give it a higher heap