Do not convert resource dirs without resources

Previously we would convert to java_resources when there were no
resources and get an error.

Test: b build //external/libphonenumber/... --config=android
Change-Id: I86f30b993a3ffdb20000f6a4c5261e2c4c74263c
diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index ad7f8d8..dbb435a 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -178,6 +178,7 @@
 		"external/libjpeg-turbo":                 Bp2BuildDefaultTrueRecursively,
 		"external/libmpeg2":                      Bp2BuildDefaultTrueRecursively,
 		"external/libpng":                        Bp2BuildDefaultTrueRecursively,
+		"external/libphonenumber":                Bp2BuildDefaultTrueRecursively,
 		"external/libvpx":                        Bp2BuildDefaultTrueRecursively,
 		"external/libyuv":                        Bp2BuildDefaultTrueRecursively,
 		"external/lz4/lib":                       Bp2BuildDefaultTrue,
@@ -1051,6 +1052,7 @@
 		"libgmock_ndk",                                            // depends on unconverted modules: libgtest_ndk_c++
 		"libnativehelper_lazy_mts_jni", "libnativehelper_mts_jni", // depends on unconverted modules: libnativetesthelper_jni, libgmock_ndk
 		"libnativetesthelper_jni",   // depends on unconverted modules: libgtest_ndk_c++
+		"libphonenumber_test",       // depends on android.test.mock
 		"libstatslog",               // depends on unconverted modules: libstatspull, statsd-aidl-ndk
 		"libstatslog_art",           // depends on unconverted modules: statslog_art.cpp, statslog_art.h
 		"linker_reloc_bench_main",   // depends on unconverted modules: liblinker_reloc_bench_*
diff --git a/bp2build/java_library_conversion_test.go b/bp2build/java_library_conversion_test.go
index 9908691..512c1e1 100644
--- a/bp2build/java_library_conversion_test.go
+++ b/bp2build/java_library_conversion_test.go
@@ -441,12 +441,13 @@
 func TestJavaLibraryResourcesWithMultipleDirs(t *testing.T) {
 	runJavaLibraryTestCase(t, Bp2buildTestCase{
 		Filesystem: map[string]string{
-			"res/a.res":  "",
-			"res1/b.res": "",
+			"res/a.res":   "",
+			"res1/b.res":  "",
+			"res2/b.java": "",
 		},
 		Blueprint: `java_library {
 	name: "java-lib-1",
-	java_resource_dirs: ["res", "res1"],
+	java_resource_dirs: ["res", "res1", "res2"],
 	sdk_version: "current",
 }`,
 		ExpectedBazelTargets: []string{
diff --git a/java/java.go b/java/java.go
index 967f8c2..99bb1b3 100644
--- a/java/java.go
+++ b/java/java.go
@@ -2826,7 +2826,7 @@
 			if resourceStripPrefix == nil && i == 0 {
 				resourceStripPrefix = resAttr.Resource_strip_prefix
 				resources = resAttr.Resources.Value
-			} else {
+			} else if !resAttr.Resources.IsEmpty() {
 				ctx.CreateBazelTargetModule(
 					bazel.BazelTargetModuleProperties{
 						Rule_class:        "java_resources",