Ensure clean shutdown without calling System.exit().

Note: it is currently not possible to restart Erjang without reloading the classes, as some (static) objects need to be re-created: ERT.scheduler, ERT.async_scheduler, ETimerTask.send_timer

src/main/java/erjang/ERT.java

@@ -1041,6 +1041,14 @@ public static void shutdown() {
 			init_pid.sendb(tup);
 		}
 	}
+
+	/**
+	 * Shutdown Kilim schedulers.
+	 */
+	/*package*/ static void shutdownSchedulers() {
+		scheduler.shutdown();
+		async_scheduler.shutdown();
+	}
 
 	static public InputStream orig_in = System.in;
 	static public PrintStream orig_out = System.out;
@@ -1069,5 +1077,4 @@ public static void debug(boolean condition, String text) {
 			debug(text);
 		}
 	}
-
 }

src/main/java/erjang/ETimerTask.java

@@ -134,4 +134,9 @@ public static long read_timer(ERef ref) {
 
 		return -1;
 	}
+
+	public static void shutdown() {
+		send_timer.cancel();
+		send_timer.purge();
+	}
 }

src/main/java/erjang/Main.java

@@ -84,7 +84,6 @@ private static String guess_erl_root() {
 
 		ERT.log.severe("Cannot find OTPROOT directory\n"
 				+ "Pass -root <dir>, or set environment variable.");
-		System.exit(-1);
 
 		return null;
 	}
@@ -162,7 +161,7 @@ public static void main(String[] args) throws Exception {
 
 		if (!(new File(erl_bootstrap_ebindir)).exists() && !erl_bootstrap_ebindir.startsWith(EFile.RESOURCE_PREFIX)) {
 			ERT.log.severe("No bootstrap classes at: "+erl_bootstrap_ebindir);
-			System.exit(1);
+			throw new IllegalArgumentException("No bootstrap classes at: "+erl_bootstrap_ebindir);
 		}
 
 		OTPMain.main(ra.toArray(new String[ra.size()]));

src/main/java/erjang/OTPMain.java

@@ -24,7 +24,6 @@
 import java.util.List;
 import java.util.logging.FileHandler;
 import java.util.logging.Handler;
-import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import erjang.driver.EDriver;
@@ -83,10 +82,18 @@ public static void start_otp_ring0(ESeq argv) {
 		EAtom am_start = EAtom.intern("start");
 		ESeq env = ERT.NIL;
 
+		// launch first (initial) process, which starts OTP
 		EProc proc = new EProc(null, am_otp_ring0, am_start, ERT.NIL.cons(argv).cons(env));
 
 		ERT.run(proc);
+
+		// wait for this process to terminate
 		proc.joinb();
+
+		// shutdown schedulers, after the first (initial) process has stopped
+		ERT.shutdownSchedulers();
+		// shutdown timer task
+		ETimerTask.shutdown();
     }
 
     protected static ESeq process_args(String[] args) {

src/main/java/erjang/console/ERLConsole.java

@@ -56,7 +56,7 @@ public ERLConsole(String title) {
     static final int HINSET = 8;
 
     public static void main(final String[] args) {
-        final ERLConsole console = new ERLConsole("Erjang Console");
+        ERLConsole console = new ERLConsole("Erjang Console");
 
         console.getContentPane().setLayout(new BorderLayout());
         console.setSize(700, 600);
@@ -77,7 +77,7 @@ public static void main(final String[] args) {
         pane.setBorder(BorderFactory.createLineBorder(Color.darkGray));
         console.getContentPane().add(pane, BorderLayout.CENTER);
 
-        StatusBar status = new StatusBar();
+        final StatusBar status = new StatusBar();
         console.getContentPane().add(status, BorderLayout.SOUTH);
 
         console.validate();
@@ -88,12 +88,20 @@ public void windowClosing(WindowEvent e) {
                 ERT.shutdown();
             }
         });
+        console.setVisible(true);
+
+        Timer timer = new Timer(true);
+        timer.schedule(new TimerTask() {
+
+			@Override
+			public void run() {
+				status.updateMemory();
+			}}, 1000, 1000);
 
         erjang.OTPMain.add_driver(tty);
 
         Thread t2 = new Thread() {
             public void run() {
-                console.setVisible(true);
                 try {
 					erjang.Main.main(args);
 				} catch (Exception e) {
@@ -108,8 +116,12 @@ public void run() {
         } catch (InterruptedException ie) {
             // ignore
         }
-
-        System.exit(0);
+        timer.cancel();
+        timer.purge();
+        timer = null;
+        console.setVisible(false);
+        console.dispose();
+        console = null;
     }
 
     private Font findFont(String otherwise, int style, int size, String[] families) {
@@ -138,7 +150,7 @@ private Font findFont(String otherwise, int style, int size, String[] families)
 @SuppressWarnings("serial")
 class StatusBar extends JPanel {
 
-	  private JLabel mem_label;
+	private JLabel mem_label;
 	private JLabel progress;
 
 	public StatusBar() {
@@ -168,13 +180,6 @@ public void run() {
 
 	    mem_label = new JLabel();
 	    add(mem_label, BorderLayout.CENTER);
-
-	    new Timer(true).schedule(new TimerTask() {
-
-			@Override
-			public void run() {
-				StatusBar.this.updateMemory();
-			}}, 1000, 1000);
 	  }
 
 	  void updateMemory() {

src/main/java/erjang/driver/EDriverTask.java

@@ -351,7 +351,6 @@ public void execute() throws Pausable {
 
 				if (log.isLoggable(Level.FINER)) {
 					log.finer("EXITING "+result);
-					System.exit(1);
 				}
 
 			} finally {

src/main/java/erjang/m/erlang/ErlProc.java

@@ -271,28 +271,35 @@ public static EObject spawn(EProc proc, EObject mod, EObject fun, EObject args)
 
 	@BIF
 	public static EObject halt(EProc proc) {
-		System.exit(0);
-		return null;
+		return halt(proc, null);
 	}
 
 	@BIF
 	public static EObject halt(EProc proc, EObject value) {
-		ESmall val = value.testSmall();
-		if (val != null) {
-			System.exit(val.value);
-			return null;
+		int exitCode = 1;
+		String message = null;
+		if (value != null) {
+			ESmall val = value.testSmall();
+			if (val != null) {
+				exitCode = val.value;
+			}
+
+			EString str = value.testString();
+			if (str != null) {
+				message = str.stringValue();
+			}
 		}
 
-		EString str = value.testString();
-		if (str != null) {		
-			// TODO: create crash file
-			log.severe("halting system: " + str.stringValue());
-			System.exit(1);
+		// TODO: create crash file
+		if (message != null) {
+			log.severe("halting system: " + message);
 		}
+		else {
+			log.info("halting system");
+		}
+		ERT.shutdown();
 
-		throw ERT.badarg(value);
-
-
+		return null;
 	}
 
 	@BIF