tiny-java-http-healthcheck.bash

#!/bin/bash -xe
cat << "JAVA" > Checker.java && javac Checker.java
import java.net.HttpURLConnection;
import java.net.URL;

public class Checker {
  public static void main(String[] args) throws Exception {
    HttpURLConnection conn =
            (HttpURLConnection) new URL(args[0])
                    .openConnection();
    System.exit(
            200 == conn.getResponseCode()
                    ? 0
                    : 1
    );
  }
}
JAVA

java Checker http://google.pl && echo OK || echo BAD

$ JAVA_8='java -ms1m -mx1m -ss228k -noverify -Djava.compiler=NONE -XX:+UseSerialGC'
$ JAVA_11='/usr/lib/jvm/java-11-openjdk-amd64/bin/java -ms1m -mx2m -ss136k -noverify -Djava.compiler=NONE -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC'

$ /usr/bin/time --verbose $JAVA_8 Checker http://google.pl 2>&1 | grep 'Maximum resident set size'
        Maximum resident set size (kbytes): 25708
$ /usr/bin/time --verbose $JAVA_11 Checker http://google.pl 2>&1 | grep 'Maximum resident set size'
        Maximum resident set size (kbytes): 32808
$ /usr/bin/time --verbose curl google.pl 2>&1 | grep 'Maximum resident set size'
        Maximum resident set size (kbytes): 10876
$ /usr/bin/time --verbose wget google.pl 2>&1 | grep 'Maximum resident set size'
        Maximum resident set size (kbytes): 4936