Issue #5681 - clearer warning on JVM Arg / System Property use

Signed-off-by: Joakim Erdfelt <[email protected]>

jetty-start/src/main/java/org/eclipse/jetty/start/Main.java

@@ -502,6 +502,10 @@ public void run()
         if (args.hasJvmArgs() || args.hasSystemProperties())
         {
             StartLog.warn("System properties and/or JVM args set.  Consider using --dry-run or --exec");
+            if (args.hasSystemProperties())
+                args.getSystemProperties().forEach((k, v) -> StartLog.warn("  Detected JVM System Property: %s=%s", k, System.getProperty(k)));
+            if (args.hasJvmArgs())
+                args.getJvmArgs().forEach((jvmArg) -> StartLog.warn("  Detected JVM Arg: %s", jvmArg));
         }
 
         ClassLoader cl = classpath.getClassLoader();

jetty-start/src/main/java/org/eclipse/jetty/start/StartArgs.java

@@ -816,7 +816,10 @@ else if (properties.size() > 0)
     public String getMainClassname()
     {
         String mainClass = System.getProperty("jetty.server", isJPMS() ? MODULE_MAIN_CLASS : MAIN_CLASS);
-        return System.getProperty("main.class", mainClass);
+        Prop mainClassProp = properties.getProp("main.class", true);
+        if (mainClassProp != null)
+            return mainClassProp.value;
+        return mainClass;
     }
 
     public String getMavenLocalRepoDir()
@@ -878,6 +881,11 @@ public Props getProperties()
         return properties;
     }
 
+    public Map<String, String> getSystemProperties()
+    {
+        return systemPropertySource;
+    }
+
     public Set<String> getSkipFileValidationModules()
     {
         return skipFileValidationModules;

jetty-start/src/test/java/org/eclipse/jetty/start/MainTest.java

@@ -19,7 +19,9 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import org.eclipse.jetty.toolchain.test.MavenTestingUtils;
 import org.junit.jupiter.api.BeforeEach;
@@ -91,6 +93,46 @@ public void testListConfig() throws Exception
         assertThat("user.dir should indicate that it was specified on the command line", userDirLine, containsString("(<command-line>)"));
     }
 
+    @Test
+    public void testUnknownDistroCommand() throws Exception
+    {
+        List<String> cmdLineArgs = new ArrayList<>();
+        File testJettyHome = MavenTestingUtils.getTestResourceDir("dist-home");
+        cmdLineArgs.add("jetty.home=" + testJettyHome);
+        cmdLineArgs.add("main.class=" + PropertyDump.class.getName());
+        cmdLineArgs.add("--module=base");
+        cmdLineArgs.add("--foople");
+        cmdLineArgs.add("-Dzed.key=0.value");
+
+        List<String> output;
+
+        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
+             PrintStream out = new PrintStream(baos, true, StandardCharsets.UTF_8))
+        {
+            PrintStream originalStream = StartLog.setStream(new PrintStream(out));
+            try
+            {
+                Main main = new Main();
+                StartArgs args = main.processCommandLine(cmdLineArgs.toArray(new String[0]));
+                main.start(args);
+                out.flush();
+                output = List.of(baos.toString(StandardCharsets.UTF_8).split(System.lineSeparator()));
+            }
+            finally
+            {
+                StartLog.setStream(originalStream);
+            }
+        }
+
+        // Test a System Property that comes from JVM
+        List<String> warnings = output.stream().filter((line) -> line.startsWith("WARN")).collect(Collectors.toList());
+        Iterator<String> warningIter = warnings.iterator();
+
+        assertThat("Announcement", warningIter.next(), containsString("System properties and/or JVM args set."));
+        assertThat("System Prop Detail", warningIter.next(), containsString("Detected JVM System Property: zed.key=0.value"));
+        assertThat("JVM Arg Detail", warningIter.next(), containsString("Detected JVM Arg: --foople"));
+    }
+
     @Test
     @Disabled("Just a bit noisy for general testing")
     public void testHelp() throws Exception

jetty-start/src/test/java/org/eclipse/jetty/start/PropertyDump.java

@@ -63,7 +63,5 @@ public static void main(String[] args)
                 }
             }
         }
-
-        System.exit(0);
     }
 }