PL/Java brings functions, triggers, and types in Java. 1.5.4 supports PostgreSQL through 12 and Java through 13 at build time and run time.

Project site: http://tada.github.io/pljava/
Release notes: http://tada.github.io/pljava/releasenotes.html

Changes in 1.5.4

• This release follows closely on 1.5.3 to correct some reported build issues
  with Java 11 and 13.
• A work-in-progress feature that can apply the SQLXML API to other
  tree-structured data types is introduced.
• Documentation updates cover changes to Application Class Data Sharing in
  recent Hotspot versions, and ahead-of-time compilation using jaotc.

Other recent user-visible changes were announced in release 1.5.3.

Please see the release notes for a more complete list of changes.

Availability:

1.5.4 is available from GitHub as a source release, which builds quickly using Maven:

Release page: https://github.com/tada/pljava/releases/tag/V1_5_4

This wiki page will add links to prebuilt packages that become available:
https://github.com/tada/pljava/wiki/Prebuilt-packages