diff --git a/internal/librarian/java/generate.go b/internal/librarian/java/generate.go
index 54d87e776..e130c07ea 100644
--- a/internal/librarian/java/generate.go
+++ b/internal/librarian/java/generate.go
@@ -59,12 +59,17 @@ func Generate(ctx context.Context, cfg *config.Config, library *config.Library,
 	if err := os.MkdirAll(outdir, 0755); err != nil {
 		return fmt.Errorf("failed to create output directory %q: %w", outdir, err)
 	}
+	// generate repo metadata prior to client because info is needed for
+	// owlbot.py to generate README.md
+	if err := generateRepoMetadata(cfg, library, outdir, googleapisDir); err != nil {
+		return fmt.Errorf("failed to generate .repo-metadata.json: %w", err)
+	}
 	for _, api := range library.APIs {
 		if err := generateAPI(ctx, cfg, api, library, googleapisDir, outdir); err != nil {
 			return fmt.Errorf("failed to generate api %q: %w", api.Path, err)
 		}
 	}
-	return postProcessLibrary(cfg, library, outdir, googleapisDir)
+	return nil
 }
 
 func generateAPI(ctx context.Context, cfg *config.Config, api *config.API, library *config.Library, googleapisDir, outdir string) error {
diff --git a/internal/librarian/java/postprocess.go b/internal/librarian/java/postprocess.go
index 7fcc4a657..ce5b1b7cd 100644
--- a/internal/librarian/java/postprocess.go
+++ b/internal/librarian/java/postprocess.go
@@ -23,11 +23,8 @@ import (
 	"strings"
 	"time"
 
-	"github.com/googleapis/librarian/internal/config"
 	"github.com/googleapis/librarian/internal/filesystem"
 	"github.com/googleapis/librarian/internal/license"
-	"github.com/googleapis/librarian/internal/repometadata"
-	"github.com/googleapis/librarian/internal/serviceconfig"
 )
 
 type postProcessParams struct {
@@ -217,108 +214,3 @@ func copyProtos(googleapisDir string, protos []string, destDir string) error {
 	}
 	return nil
 }
-
-// postProcessLibrary coordinates all library-level post-processing tasks,
-// such as generating .repo-metadata.json.
-func postProcessLibrary(cfg *config.Config, library *config.Library, outDir, googleapisDir string) error {
-	// TODO(https://github.com/googleapis/librarian/issues/4217): update pom files.
-	// TODO(https://github.com/googleapis/librarian/issues/4218): generate README.md
-	metadata, err := deriveRepoMetadata(cfg, library, googleapisDir)
-	if err != nil {
-		return fmt.Errorf("failed to derive repo metadata: %w", err)
-	}
-	if err := metadata.write(outDir); err != nil {
-		return fmt.Errorf("failed to write .repo-metadata.json: %w", err)
-	}
-	return nil
-}
-
-// deriveRepoMetadata constructs the repoMetadata for a Java library using
-// information from the primary service configuration and library-level overrides.
-func deriveRepoMetadata(cfg *config.Config, library *config.Library, googleapisDir string) (*repoMetadata, error) {
-	serviceconfig.SortAPIs(library.APIs)
-	sharedMetadata, err := repometadata.FromLibrary(cfg, library, googleapisDir)
-	if err != nil {
-		return nil, err
-	}
-
-	metadata := &repoMetadata{
-		APIShortname:         sharedMetadata.APIShortname,
-		NamePretty:           sharedMetadata.NamePretty,
-		ProductDocumentation: sharedMetadata.ProductDocumentation,
-		APIDescription:       sharedMetadata.APIDescription,
-		ReleaseLevel:         sharedMetadata.ReleaseLevel,
-		Language:             config.LanguageJava,
-		Repo:                 sharedMetadata.Repo,
-		RepoShort:            fmt.Sprintf("%s-%s", config.LanguageJava, library.Name),
-		DistributionName:     sharedMetadata.DistributionName,
-		APIID:                sharedMetadata.APIID,
-		LibraryType:          repometadata.GAPICAutoLibraryType,
-		RequiresBilling:      true,
-	}
-
-	// Java-specific overrides and optional fields
-	if library.Java.APIIDOverride != "" {
-		metadata.APIID = library.Java.APIIDOverride
-	}
-	if library.Java.APIDescriptionOverride != "" {
-		metadata.APIDescription = library.Java.APIDescriptionOverride
-	}
-	if library.Java.DistributionNameOverride != "" {
-		metadata.DistributionName = library.Java.DistributionNameOverride
-	}
-	if library.Java.IssueTrackerOverride != "" {
-		metadata.IssueTracker = library.Java.IssueTrackerOverride
-	}
-	if library.Java.LibraryTypeOverride != "" {
-		metadata.LibraryType = library.Java.LibraryTypeOverride
-	}
-	if library.Java.NamePrettyOverride != "" {
-		metadata.NamePretty = library.Java.NamePrettyOverride
-	}
-	if library.Java.ProductDocumentationOverride != "" {
-		metadata.ProductDocumentation = library.Java.ProductDocumentationOverride
-	}
-	if library.Java.ClientDocumentationOverride != "" {
-		metadata.ClientDocumentation = library.Java.ClientDocumentationOverride
-	}
-	metadata.RequiresBilling = !library.Java.BillingNotRequired
-	// Java only fields
-	metadata.CodeownerTeam = library.Java.CodeownerTeam
-	metadata.ExtraVersionedModules = library.Java.ExtraVersionedModules
-	metadata.ExcludedDependencies = library.Java.ExcludedDependencies
-	metadata.ExcludedPoms = library.Java.ExcludedPoms
-	metadata.MinJavaVersion = library.Java.MinJavaVersion
-	metadata.RecommendedPackage = library.Java.RecommendedPackage
-	metadata.RestDocumentation = library.Java.RestDocumentation
-	metadata.RpcDocumentation = library.Java.RpcDocumentation
-
-	// distribution_name default for Java is groupId:artifactId
-	if !strings.Contains(metadata.DistributionName, ":") {
-		metadata.DistributionName = deriveDistributionName(library)
-	}
-	// Default ClientDocumentation uses artifact ID
-	if metadata.ClientDocumentation == "" {
-		parts := strings.Split(metadata.DistributionName, ":")
-		artifactID := parts[len(parts)-1]
-		metadata.ClientDocumentation = fmt.Sprintf("https://cloud.google.com/java/docs/reference/%s/latest/overview", artifactID)
-	}
-	// transport
-	apiCfg, err := serviceconfig.Find(googleapisDir, library.APIs[0].Path, config.LanguageJava)
-	if err != nil {
-		return nil, fmt.Errorf("failed to find api config: %w", err)
-	}
-	transport := serviceconfig.GRPCRest
-	if apiCfg != nil {
-		transport = apiCfg.Transport(config.LanguageJava)
-	}
-	switch transport {
-	case "grpc":
-		metadata.Transport = "grpc"
-	case "rest":
-		metadata.Transport = "http"
-	default:
-		metadata.Transport = "both"
-	}
-	return metadata, nil
-}
diff --git a/internal/librarian/java/postprocess_test.go b/internal/librarian/java/postprocess_test.go
index f09ab6580..1a13f9406 100644
--- a/internal/librarian/java/postprocess_test.go
+++ b/internal/librarian/java/postprocess_test.go
@@ -23,9 +23,6 @@ import (
 	"strings"
 
 	"testing"
-
-	"github.com/google/go-cmp/cmp"
-	"github.com/googleapis/librarian/internal/config"
 )
 
 func TestPostProcessAPI(t *testing.T) {
@@ -307,51 +304,3 @@ func TestAddMissingHeaders(t *testing.T) {
 		})
 	}
 }
-
-func TestDeriveRepoMetadata_Overrides(t *testing.T) {
-	t.Parallel()
-	apiPath := "google/cloud/secretmanager/v1"
-	googleapis := "internal/testdata/googleapis"
-
-	cfg := &config.Config{
-		Language: config.LanguageJava,
-		Repo:     "googleapis/google-cloud-java",
-	}
-	library := &config.Library{
-		Name: "secretmanager",
-		APIs: []*config.API{{Path: apiPath}},
-		Java: &config.JavaModule{
-			GroupID:                      "com.custom",
-			DistributionNameOverride:     "com.custom:custom-artifact",
-			APIIDOverride:                "custom.googleapis.com",
-			APIDescriptionOverride:       "Custom description",
-			NamePrettyOverride:           "Custom Pretty Name",
-			ProductDocumentationOverride: "https://custom.docs",
-			ClientDocumentationOverride:  "https://custom.client.docs",
-			BillingNotRequired:           true,
-			LibraryTypeOverride:          "OTHER",
-		},
-	}
-	got, err := deriveRepoMetadata(cfg, library, googleapis)
-	if err != nil {
-		t.Fatalf("deriveRepoMetadata failed: %v", err)
-	}
-	want := &repoMetadata{
-		NamePretty:           "Custom Pretty Name",
-		ProductDocumentation: "https://custom.docs",
-		APIDescription:       "Custom description",
-		ClientDocumentation:  "https://custom.client.docs",
-		ReleaseLevel:         "stable",
-		Transport:            "both",
-		Language:             "java",
-		Repo:                 "googleapis/google-cloud-java",
-		RepoShort:            "java-secretmanager",
-		DistributionName:     "com.custom:custom-artifact",
-		APIID:                "custom.googleapis.com",
-		LibraryType:          "OTHER",
-		RequiresBilling:      false,
-	}
-	if diff := cmp.Diff(want, got, cmp.AllowUnexported(repoMetadata{})); diff != "" {
-		t.Errorf("mismatch (-want +got):\n%s", diff)
-	}
-}
diff --git a/internal/librarian/java/repometadata.go b/internal/librarian/java/repometadata.go
index c1775a64e..fd26ffedc 100644
--- a/internal/librarian/java/repometadata.go
+++ b/internal/librarian/java/repometadata.go
@@ -14,7 +14,14 @@
 
 package java
 
-import "github.com/googleapis/librarian/internal/repometadata"
+import (
+	"fmt"
+	"strings"
+
+	"github.com/googleapis/librarian/internal/config"
+	"github.com/googleapis/librarian/internal/repometadata"
+	"github.com/googleapis/librarian/internal/serviceconfig"
+)
 
 // repoMetadata represents the .repo-metadata.json file structure for Java.
 //
@@ -63,3 +70,100 @@ type repoMetadata struct {
 func (metadata *repoMetadata) write(libraryOutputDir string) error {
 	return repometadata.WriteJSON(metadata, "  ", libraryOutputDir, ".repo-metadata.json")
 }
+
+// generateRepoMetadata coordinates all library-level post-processing tasks,
+// such as generating .repo-metadata.json.
+func generateRepoMetadata(cfg *config.Config, library *config.Library, outDir, googleapisDir string) error {
+	metadata, err := deriveRepoMetadata(cfg, library, googleapisDir)
+	if err != nil {
+		return fmt.Errorf("failed to derive repo metadata: %w", err)
+	}
+	if err := metadata.write(outDir); err != nil {
+		return fmt.Errorf("failed to write .repo-metadata.json: %w", err)
+	}
+	return nil
+}
+
+// deriveRepoMetadata constructs the repoMetadata for a Java library using
+// information from the primary service configuration and library-level overrides.
+func deriveRepoMetadata(cfg *config.Config, library *config.Library, googleapisDir string) (*repoMetadata, error) {
+	serviceconfig.SortAPIs(library.APIs)
+	sharedMetadata, err := repometadata.FromLibrary(cfg, library, googleapisDir)
+	if err != nil {
+		return nil, err
+	}
+
+	metadata := &repoMetadata{
+		APIShortname:         sharedMetadata.APIShortname,
+		NamePretty:           sharedMetadata.NamePretty,
+		ProductDocumentation: sharedMetadata.ProductDocumentation,
+		APIDescription:       sharedMetadata.APIDescription,
+		ReleaseLevel:         sharedMetadata.ReleaseLevel,
+		Language:             config.LanguageJava,
+		Repo:                 sharedMetadata.Repo,
+		RepoShort:            fmt.Sprintf("%s-%s", config.LanguageJava, library.Name),
+		DistributionName:     sharedMetadata.DistributionName,
+		APIID:                sharedMetadata.APIID,
+		LibraryType:          repometadata.GAPICAutoLibraryType,
+		RequiresBilling:      true,
+	}
+
+	// Java-specific overrides and optional fields
+	if library.Java != nil {
+		if library.Java.APIIDOverride != "" {
+			metadata.APIID = library.Java.APIIDOverride
+		}
+		if library.Java.APIDescriptionOverride != "" {
+			metadata.APIDescription = library.Java.APIDescriptionOverride
+		}
+		if library.Java.DistributionNameOverride != "" {
+			metadata.DistributionName = library.Java.DistributionNameOverride
+		}
+		if library.Java.IssueTrackerOverride != "" {
+			metadata.IssueTracker = library.Java.IssueTrackerOverride
+		}
+		if library.Java.LibraryTypeOverride != "" {
+			metadata.LibraryType = library.Java.LibraryTypeOverride
+		}
+		if library.Java.NamePrettyOverride != "" {
+			metadata.NamePretty = library.Java.NamePrettyOverride
+		}
+		if library.Java.ProductDocumentationOverride != "" {
+			metadata.ProductDocumentation = library.Java.ProductDocumentationOverride
+		}
+		if library.Java.ClientDocumentationOverride != "" {
+			metadata.ClientDocumentation = library.Java.ClientDocumentationOverride
+		}
+		metadata.RequiresBilling = !library.Java.BillingNotRequired
+		// Java only fields
+		metadata.CodeownerTeam = library.Java.CodeownerTeam
+		metadata.ExtraVersionedModules = library.Java.ExtraVersionedModules
+		metadata.ExcludedDependencies = library.Java.ExcludedDependencies
+		metadata.ExcludedPoms = library.Java.ExcludedPoms
+		metadata.MinJavaVersion = library.Java.MinJavaVersion
+		metadata.RecommendedPackage = library.Java.RecommendedPackage
+		metadata.RestDocumentation = library.Java.RestDocumentation
+		metadata.RpcDocumentation = library.Java.RpcDocumentation
+	}
+
+	// distribution_name default for Java is groupId:artifactId
+	if !strings.Contains(metadata.DistributionName, ":") {
+		metadata.DistributionName = deriveDistributionName(library)
+	}
+	// Default ClientDocumentation uses artifact ID
+	if metadata.ClientDocumentation == "" {
+		parts := strings.Split(metadata.DistributionName, ":")
+		artifactID := parts[len(parts)-1]
+		metadata.ClientDocumentation = fmt.Sprintf("https://cloud.google.com/java/docs/reference/%s/latest/overview", artifactID)
+	}
+	// transport
+	apiCfg, err := serviceconfig.Find(googleapisDir, library.APIs[0].Path, config.LanguageJava)
+	if err != nil {
+		return nil, fmt.Errorf("failed to find api config: %w", err)
+	}
+	metadata.Transport = "both"
+	if apiCfg != nil {
+		metadata.Transport = apiCfg.RepoMetadataTransport(config.LanguageJava)
+	}
+	return metadata, nil
+}
diff --git a/internal/librarian/java/repometadata_test.go b/internal/librarian/java/repometadata_test.go
index 50779ad4f..912823054 100644
--- a/internal/librarian/java/repometadata_test.go
+++ b/internal/librarian/java/repometadata_test.go
@@ -15,29 +15,33 @@
 package java
 
 import (
+	"encoding/json"
 	"os"
 	"path/filepath"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/googleapis/librarian/internal/config"
+	"github.com/googleapis/librarian/internal/sample"
 )
 
 func TestRepoMetadata_write(t *testing.T) {
+	s := sample.RepoMetadata()
 	want := &repoMetadata{
-		APIShortname:         "secretmanager",
-		NamePretty:           "Secret Manager",
-		ProductDocumentation: "https://cloud.google.com/secret-manager/",
-		APIDescription:       "Stores sensitive data such as API keys, passwords, and certificates. Provides convenience while improving security.",
+		APIShortname:         s.APIShortname,
+		NamePretty:           s.NamePretty,
+		ProductDocumentation: s.ProductDocumentation,
+		APIDescription:       s.APIDescription,
 		ClientDocumentation:  "https://cloud.google.com/java/docs/reference/google-cloud-secretmanager/latest/overview",
-		ReleaseLevel:         "stable",
+		ReleaseLevel:         s.ReleaseLevel,
 		Transport:            "grpc",
 		Language:             "java",
 		Repo:                 "googleapis/google-cloud-java",
 		RepoShort:            "java-secretmanager",
 		DistributionName:     "com.google.cloud:google-cloud-secretmanager",
-		LibraryType:          "GAPIC_AUTO",
+		LibraryType:          s.LibraryType,
 		CodeownerTeam:        "cloud-java-team",
-		IssueTracker:         "https://issuetracker.google.com/issues/new?component=187210&template=0",
+		IssueTracker:         s.IssueTracker,
 		RestDocumentation:    "https://example.com/rest",
 		RpcDocumentation:     "https://example.com/rpc",
 		RecommendedPackage:   "com.google.cloud.secretmanager.v1",
@@ -53,34 +57,63 @@ func TestRepoMetadata_write(t *testing.T) {
 	if _, err := os.Stat(gotPath); err != nil {
 		t.Fatalf("os.Stat(%q) = %v, want nil", gotPath, err)
 	}
-
 	gotBytes, err := os.ReadFile(gotPath)
 	if err != nil {
 		t.Fatalf("os.ReadFile(%q) = %v, want nil", gotPath, err)
 	}
-
-	const wantJSON = `{
-  "api_shortname": "secretmanager",
-  "name_pretty": "Secret Manager",
-  "product_documentation": "https://cloud.google.com/secret-manager/",
-  "api_description": "Stores sensitive data such as API keys, passwords, and certificates. Provides convenience while improving security.",
-  "client_documentation": "https://cloud.google.com/java/docs/reference/google-cloud-secretmanager/latest/overview",
-  "release_level": "stable",
-  "transport": "grpc",
-  "language": "java",
-  "repo": "googleapis/google-cloud-java",
-  "repo_short": "java-secretmanager",
-  "distribution_name": "com.google.cloud:google-cloud-secretmanager",
-  "library_type": "GAPIC_AUTO",
-  "requires_billing": false,
-  "codeowner_team": "cloud-java-team",
-  "issue_tracker": "https://issuetracker.google.com/issues/new?component=187210\u0026template=0",
-  "rest_documentation": "https://example.com/rest",
-  "rpc_documentation": "https://example.com/rpc",
-  "recommended_package": "com.google.cloud.secretmanager.v1",
-  "min_java_version": 8
-}`
-	if diff := cmp.Diff(wantJSON, string(gotBytes)); diff != "" {
+	var got repoMetadata
+	if err := json.Unmarshal(gotBytes, &got); err != nil {
+		t.Fatalf("json.Unmarshal() = %v, want nil", err)
+	}
+	if diff := cmp.Diff(want, &got, cmp.AllowUnexported(repoMetadata{})); diff != "" {
 		t.Errorf("write() mismatch (-want +got):\n%s", diff)
 	}
 }
+
+func TestDeriveRepoMetadata_Overrides(t *testing.T) {
+	t.Parallel()
+	apiPath := "google/cloud/secretmanager/v1"
+	googleapis := "internal/testdata/googleapis"
+
+	cfg := sample.Config()
+	cfg.Language = config.LanguageJava
+	cfg.Repo = "googleapis/google-cloud-java"
+	library := &config.Library{
+		Name: "secretmanager",
+		APIs: []*config.API{{Path: apiPath}},
+		Java: &config.JavaModule{
+			GroupID:                      "com.custom",
+			DistributionNameOverride:     "com.custom:custom-artifact",
+			APIIDOverride:                "custom.googleapis.com",
+			APIDescriptionOverride:       "Custom description",
+			NamePrettyOverride:           "Custom Pretty Name",
+			ProductDocumentationOverride: "https://custom.docs",
+			ClientDocumentationOverride:  "https://custom.client.docs",
+			BillingNotRequired:           true,
+			LibraryTypeOverride:          "OTHER",
+		},
+	}
+	got, err := deriveRepoMetadata(cfg, library, googleapis)
+	if err != nil {
+		t.Fatalf("deriveRepoMetadata failed: %v", err)
+	}
+	s := sample.RepoMetadata()
+	want := &repoMetadata{
+		NamePretty:           "Custom Pretty Name",
+		ProductDocumentation: "https://custom.docs",
+		APIDescription:       "Custom description",
+		ClientDocumentation:  "https://custom.client.docs",
+		ReleaseLevel:         s.ReleaseLevel,
+		Transport:            "both",
+		Language:             cfg.Language,
+		Repo:                 cfg.Repo,
+		RepoShort:            "java-secretmanager",
+		DistributionName:     "com.custom:custom-artifact",
+		APIID:                "custom.googleapis.com",
+		LibraryType:          "OTHER",
+		RequiresBilling:      false,
+	}
+	if diff := cmp.Diff(want, got, cmp.AllowUnexported(repoMetadata{})); diff != "" {
+		t.Errorf("mismatch (-want +got):\n%s", diff)
+	}
+}
diff --git a/internal/serviceconfig/api.go b/internal/serviceconfig/api.go
index 2ca540ab2..7878767a7 100644
--- a/internal/serviceconfig/api.go
+++ b/internal/serviceconfig/api.go
@@ -187,6 +187,26 @@ func (api *API) RepoMetadataReleaseLevel(language string) string {
 	return api.ReleaseLevel(language)
 }
 
+// RepoMetadataTransport returns the transport for repo metadata.
+//
+// TODO(https://github.com/googleapis/librarian/issues/4854): delete
+// once the issue is resolved.
+// For Java, it maps the transport to "grpc", "http", or "both".
+func (api *API) RepoMetadataTransport(language string) string {
+	transport := api.Transport(language)
+	if language == config.LanguageJava {
+		switch transport {
+		case GRPC:
+			return "grpc"
+		case Rest:
+			return "http"
+		default:
+			return "both"
+		}
+	}
+	return string(transport)
+}
+
 var (
 	//go:embed sdk.yaml
 	sdkYaml []byte
diff --git a/internal/serviceconfig/api_test.go b/internal/serviceconfig/api_test.go
index 859cf4194..ae172a34b 100644
--- a/internal/serviceconfig/api_test.go
+++ b/internal/serviceconfig/api_test.go
@@ -302,3 +302,64 @@ func TestGetTransport(t *testing.T) {
 		})
 	}
 }
+
+func TestRepoMetadataTransport(t *testing.T) {
+	for _, test := range []struct {
+		name     string
+		sc       *API
+		language string
+		want     string
+	}{
+		{
+			name:     "java, default",
+			sc:       &API{},
+			language: config.LanguageJava,
+			want:     "both",
+		},
+		{
+			name: "java, grpc",
+			sc: &API{
+				Transports: map[string]Transport{config.LanguageJava: GRPC},
+			},
+			language: config.LanguageJava,
+			want:     "grpc",
+		},
+		{
+			name: "java, rest",
+			sc: &API{
+				Transports: map[string]Transport{config.LanguageJava: Rest},
+			},
+			language: config.LanguageJava,
+			want:     "http",
+		},
+		{
+			name:     "non-java, default",
+			sc:       &API{},
+			language: config.LanguageGo,
+			want:     "grpc+rest",
+		},
+		{
+			name: "non-java, grpc",
+			sc: &API{
+				Transports: map[string]Transport{config.LanguageGo: GRPC},
+			},
+			language: config.LanguageGo,
+			want:     "grpc",
+		},
+		{
+			name: "non-java, rest",
+			sc: &API{
+				Transports: map[string]Transport{config.LanguageGo: Rest},
+			},
+			language: config.LanguageGo,
+			want:     "rest",
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			got := test.sc.RepoMetadataTransport(test.language)
+			if diff := cmp.Diff(test.want, got); diff != "" {
+				t.Errorf("mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}