My understanding is that jarsigner is packaged with OpenJDK, which I've installed by running
sudo amazon-linux-extras install java-openjdk11
Now I have a bunch of synlinks to the jdk, like so:
$ ll /etc/alternatives/jre*
lrwxrwxrwx 1 root root 60 Feb 16 01:00 /etc/alternatives/jre -> /usr/lib/jvm/java-11-openjdk-11.0.13.0.8-1.amzn2.0.3.aarch64
lrwxrwxrwx 1 root root 60 Feb 16 01:00 /etc/alternatives/jre_11 -> /usr/lib/jvm/java-11-openjdk-11.0.13.0.8-1.amzn2.0.3.aarch64
lrwxrwxrwx 1 root root 59 Feb 16 01:00 /etc/alternatives/jre_11_openjdk -> /usr/lib/jvm/jre-11-openjdk-11.0.13.0.8-1.amzn2.0.3.aarch64
lrwxrwxrwx 1 root root 60 Feb 16 01:00 /etc/alternatives/jre_openjdk -> /usr/lib/jvm/java-11-openjdk-11.0.13.0.8-1.amzn2.0.3.aarch64
However, I don't have jarsigner in the bin directory:
$ ll /etc/alternatives/jre/bin
total 656
-rwxr-xr-x 1 root root 71368 Dec 17 12:16 alt-java
-rwxr-xr-x 1 root root 71360 Dec 17 12:16 java
-rwxr-xr-x 1 root root 71392 Dec 17 12:16 jjs
-rwxr-xr-x 1 root root 71384 Dec 17 12:16 keytool
-rwxr-xr-x 1 root root 71384 Dec 17 12:16 pack200
-rwxr-xr-x 1 root root 71376 Dec 17 12:16 rmid
-rwxr-xr-x 1 root root 71384 Dec 17 12:16 rmiregistry
-rwxr-xr-x 1 root root 152440 Dec 17 12:16 unpack200
What else do I need to do to install this binary?
It appears Amazon follows the RedHat packaging scheme with JRE and JDK separated, as Sun/Oracle used to (and the JRE split into GUI and 'headless', not an issue for you):
$ yum list 'java-11-openjdk*'
Loaded plugins: extras_suggestions, langpacks, priorities, update-motd
Installed Packages
java-11-openjdk.x86_64 1:11.0.13.0.8-1.amzn2.0.3 @amzn2extra-java-openjdk11
java-11-openjdk-headless.x86_64 1:11.0.13.0.8-1.amzn2.0.3 @amzn2extra-java-openjdk11
Available Packages
java-11-openjdk-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-demo.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-demo-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-devel.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-devel-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-headless-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-javadoc.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-javadoc-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-javadoc-zip.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-javadoc-zip-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-jmods.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-jmods-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-src.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-src-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-static-libs.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
java-11-openjdk-static-libs-debug.x86_64 1:11.0.13.0.8-1.amzn2.0.3 amzn2extra-java-openjdk11
sudo yum install java-11-openjdk-devel should do it.