Polish

See gh-48239

Author: snicoll

configuration-metadata/spring-boot-configuration-metadata/src/main/java/org/springframework/boot/configurationmetadata/ConfigurationMetadataRepositoryJsonBuilder.java

@@ -33,7 +33,7 @@
  */
 public final class ConfigurationMetadataRepositoryJsonBuilder {
 
-	private Charset defaultCharset = StandardCharsets.UTF_8;
+	private final Charset defaultCharset;
 
 	private final JsonReader reader = new JsonReader();
 
@@ -91,11 +91,14 @@ public ConfigurationMetadataRepository build() {
 		return result;
 	}
 
-	private SimpleConfigurationMetadataRepository add(InputStream in, Charset charset) {
+	private SimpleConfigurationMetadataRepository add(InputStream in, Charset charset) throws IOException {
 		try {
 			RawConfigurationMetadata metadata = this.reader.read(in, charset);
 			return create(metadata);
 		}
+		catch (IOException ex) {
+			throw ex;
+		}
 		catch (Exception ex) {
 			throw new IllegalStateException("Failed to read configuration metadata", ex);
 		}