Add a default logging handler, in case the user doesn't provide any.

classpath/java/util/logging/Logger.java

@@ -6,7 +6,11 @@ import java.util.List;
 
 public class Logger {
   private final String name;
-  private static final ArrayList<Handler> handlers = new ArrayList<Handler>();
+  private static final ArrayList<Handler> handlers;
+  static {
+    handlers = new ArrayList<Handler>();
+    handlers.add(new DefaultHandler());
+  }
 
   public static Logger getLogger(String name) {
     return new Logger(name);
@@ -17,7 +21,7 @@ public class Logger {
   }
 
   public List<Handler> getHandlers() {
-    return handlers;
+    return new ArrayList<Handler>(handlers);
   }
 
   public void addHandler(Handler handler) {
@@ -64,4 +68,57 @@ public class Logger {
   public void setLevel(Level level) {
     // Currently ignored
   }
+
+  private static class DefaultHandler extends Handler {
+    private static final int NAME_WIDTH = 18;
+    private static final int METHOD_WIDTH = 20;
+    private static final int LEVEL_WIDTH = 8;
+
+    public Object clone() { return this; }
+    public void close() { }
+    public void flush() { }
+
+    private void maybeLogThrown(StringBuilder sb, Throwable t) {
+      if (t != null) {
+        sb.append("\nCaused by: ");
+        sb.append(t.getClass().getName());
+        sb.append(": ");
+        sb.append(t.getMessage());
+        sb.append('\n');
+
+        for (StackTraceElement elt : t.getStackTrace()) {
+          sb.append('\t');
+          sb.append(elt.getClassName());
+          sb.append('.');
+          sb.append(elt.getMethodName());
+          sb.append("(line");
+          sb.append(':');
+          sb.append(elt.getLineNumber());
+          sb.append(')');
+          sb.append('\n');
+        }
+        maybeLogThrown(sb, t.getCause());
+      }
+    }
+
+    private void indent(StringBuilder sb, int amount) {
+      do {
+        sb.append(' ');
+      } while (--amount > 0);
+    }
+
+    public void publish(LogRecord r) {
+      StringBuilder sb = new StringBuilder();
+      sb.append(r.getLoggerName());
+      indent(sb, NAME_WIDTH - r.getLoggerName().length());
+      sb.append(r.getSourceMethodName());
+      indent(sb, METHOD_WIDTH - r.getSourceMethodName().length());
+      sb.append(r.getLevel().getName());
+      indent(sb, LEVEL_WIDTH - r.getLevel().getName().length());
+      sb.append(r.getMessage());
+      maybeLogThrown(sb, r.getThrown());
+      System.out.println(sb.toString());
+    }
+  }
+
 }

test/Logging.java

@@ -92,11 +92,15 @@ public class Logging {
     throw new Exception("Started here");
   }
 
+  private static final boolean useCustomHandler = true;
   public static void main(String args[]) {
+    if (useCustomHandler) {
       Logger root = Logger.getLogger("");
       root.addHandler(new MyHandler());
       for (Handler h : root.getHandlers()) root.removeHandler(h);
       root.addHandler(new MyHandler());
+    }
+
     Logging me = new Logging();
     me.run();
   }