Merge branch 'improvement/JAL-1988+JAL-3416_Java8_macOS_APQHandlers_and_FlatLaF_optio...

diff --cc src/jalview/bin/Jalview.java
index fc4c821,ca850eb..fd1783a
--- 1/src/jalview/bin/Jalview.java
--- 2/src/jalview/bin/Jalview.java
+++ b/src/jalview/bin/Jalview.java
@@@ -47,9 -49,10 +49,11 @@@ import javax.swing.SwingUtilities
  import javax.swing.UIManager;
  import javax.swing.UIManager.LookAndFeelInfo;
  
+ import com.formdev.flatlaf.FlatLightLaf;
+ import com.formdev.flatlaf.util.SystemInfo;
  import com.threerings.getdown.util.LaunchUtil;
  
 +//import edu.stanford.ejalbert.launching.IBrowserLaunching;
  import groovy.lang.Binding;
  import groovy.util.GroovyScriptEngine;
  import jalview.ext.so.SequenceOntology;
@@@ -912,9 -906,16 +916,16 @@@ public class Jalvie
        lafSet = setNimbusLookAndFeel();
        if (!lafSet)
        {
 -        Cache.log.error("Could not set requested laf=" + laf);
 +        Console.error("Could not set requested laf=" + laf);
        }
        break;
+     case "flat":
+       lafSet = setFlatLookAndFeel();
+       if (!lafSet)
+       {
 -        Cache.log.error("Could not set requested laf=" + laf);
++        Console.error("Could not set requested laf=" + laf);
+       }
+       break;
      case "quaqua":
        lafSet = setQuaquaLookAndFeel();
        if (!lafSet)