I am using Debian 10.6.
$ sudo apt install openjdk-16-jre-headless Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package openjdk-16-jre-headless Here is my package list. Notice how there is only openjdk 11, and nothing else.
$ apt search openjdk Sorting... Done Full Text Search... Done default-jdk/oldstable 2:1.11-71 i386 Standard Java or Java compatible Development Kit default-jdk-doc/oldstable 2:1.11-71 amd64 Standard Java or Java compatible Development Kit (documentation) default-jdk-headless/oldstable,now 2:1.11-71 amd64 [installed,automatic] Standard Java or Java compatible Development Kit (headless) default-jre/oldstable,now 2:1.11-71 amd64 [installed,automatic] Standard Java or Java compatible Runtime default-jre-headless/oldstable,now 2:1.11-71 amd64 [installed,automatic] Standard Java or Java compatible Runtime (headless) java-package/oldstable,oldstable 0.62 all Utility for creating Java Debian packages jtreg/oldstable,oldstable 4.2-b14-1 all Regression Test Harness for the OpenJDK platform libhsdis0-fcml/oldstable 1.1.3-3 amd64 HotSpot disassembler plugin using FCML libreoffice/oldstable 1:6.1.5-3+deb10u7 amd64 [upgradable from: 1:6.1.5-3+deb10u6] office productivity suite (metapackage) nvidia-openjdk-8-jre/oldstable 9.+8u77~9.2.148-7+deb10u1 amd64 NVIDIA provided OpenJDK Java runtime, using Hotspot JIT openjdk-11-dbg/oldstable 11.0.13+8-1~deb10u1 amd64 
