Chapter 4. Red Hat build of OpenJDK features

The latest Red Hat build of OpenJDK 11 release might include new features. Additionally, the latest release might enhance, deprecate, or remove features that originated from earlier Red Hat build of OpenJDK 11 releases.

Red Hat build of OpenJDK new features and enhancements

Review the following release notes to understand new features and feature enhancements that Red Hat build of OpenJDK 11.0.27 provides:

Warnings from jarsigner tool about removed file entries

In earlier Red Hat build of OpenJDK releases, when a file was removed from a signed JAR file but the file signature was still present, the jarsigner tool did not detect this situation.

In Red Hat build of OpenJDK 11.0.27, you can use the jarsigner ‑verify command to check that every signature has a matching file entry. If any mismatch exists, this command prints a warning. To display the names of any mismatched entries, add the ‑verbose option to the command.

See JDK-8309841 (JDK Bug System).

Distrust of TLS server certificates issued after 15 April 2025 and anchored by Camerfirma root CAs

In accordance with similar plans that Google, Mozilla, Apple, and Microsoft recently announced, Red Hat build of OpenJDK 11.0.27 distrusts TLS certificates that are issued after 15 April 2025 and anchored by Camerfirma root certificates.

Red Hat build of OpenJDK will continue to trust certificates that are issued on or before 15 April 2025 until these certificates expire.

If a server’s certificate chain is anchored by an affected certificate, any attempts to negotiate a TLS session now fail with an exception to indicate that the trust anchor is not trusted. For example:

TLS server certificate issued after 2025-04-15 and anchored by a distrusted legacy Camerfirma root CA: CN=Chambers of Commerce Root -
2008, O=AC Camerfirma S.A., SERIALNUMBER=A82743287, L=Madrid (see current address at www.camerfirma.com/address), C=EU

You can check whether this change affects a certificate in a JDK keystore by using the following keytool command:

keytool -v -list -alias <your_server_alias> -keystore <your_keystore_filename>

If this change affects any certificate in the chain, update this certificate or contact the organisation that is responsible for managing the certificate.

If you want to continue using TLS server certificates that are anchored by Camerfirma root certificates, you can remove CAMERFIRMA_TLS from the jdk.security.caDistrustPolicies security property either by modifying the java.security configuration file or by using the java.security.properties system property.

These restrictions apply to the following Camerfirma root certificates that Red Hat build of OpenJDK includes:

See JDK-8346587 (JDK Bug System).

Fix for invokedynamic string concatenation changing order of operations

The Indify String Concatenation feature that was added in OpenJDK 9 through JEP-280 introduced a regression in the order in which string concatenation expressions are evaluated. The Java Language Specification requires that operands are fully evaluated in left-to-right order. However, with the introduction of invokedynamic (indy) call generation by the javac compiler for evaluating string concatenation expressions, all operands were evaluated in order but not converted to strings. In this situation, each operand was converted to a string only later.

For example, consider the following code, where the third argument of the concatenation has the side effect of altering the value of builder to "goodbye":

StringBuilder builder = new StringBuilder("good");
return "" + builder + builder.append("bye");

Based on the preceding example, in earlier releases, the Indify String Concatenation feature did not convert the second argument to a string until after the builder.append method altered the StringBuilder object. In this situation, the concatenation incorrectly became "" + "goodbye" + "goodbye", which produced "goodbyegoodbye" as the output.

In Red Hat build of OpenJDK 11.0.27, string concatenation evaluates and eagerly converts each argument to a string in left-to-right order. In this situation, the concatenation correctly becomes "" + "good" + "goodbye", which produces "goodgoodbye" as the output.

See JDK-8273914 (JDK Bug System).