diff -r 6521875cb63e -r 8f60bd284bf4 nashorn/samples/exceptionswallow.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/samples/exceptionswallow.js	Mon Sep 14 16:13:10 2015 +0530
@@ -0,0 +1,136 @@
+#// Usage: jjs exceptionswallow.js -- <directory>
+
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ *   - Neither the name of Oracle nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+// This example demonstrates Java subclassing by Java.extend
+// and javac Compiler and Tree API. This example looks for
+// empty catch blocks ("exception swallow") and reports those.
+
+if (arguments.length == 0) {
+    print("Usage: jjs exceptionswallow.js -- <directory>");
+    exit(1);
+}
+ 
+// Java types used
+var File = Java.type("java.io.File");
+var Files = Java.type("java.nio.file.Files");
+var StringArray = Java.type("java.lang.String[]");
+var ToolProvider = Java.type("javax.tools.ToolProvider");
+var Tree = Java.type("com.sun.source.tree.Tree");
+var EmptyStatementTree = Java.type("com.sun.source.tree.EmptyStatementTree");
+var Trees = Java.type("com.sun.source.util.Trees");
+var TreeScanner = Java.type("com.sun.source.util.TreeScanner");
+
+// printEmptyCatch
+
+function printEmptyCatch() {
+    // get the system compiler tool
+    var compiler = ToolProvider.systemJavaCompiler;
+    // get standard file manager
+    var fileMgr = compiler.getStandardFileManager(null, null, null);
+    // Using Java.to convert script array (arguments) to a Java String[]
+    var compUnits = fileMgr.getJavaFileObjects(
+        Java.to(arguments, StringArray));
+    // create a new compilation task
+    var task = compiler.getTask(null, fileMgr, null, null, null, compUnits);
+
+    // SourcePositions object to get positions of AST nodes
+    var sourcePositions = Trees.instance(task).sourcePositions;
+
+    // subclass SimpleTreeVisitor - to print empty catch
+    var EmptyCatchFinder = Java.extend(TreeScanner);
+   
+    function hasOnlyEmptyStats(stats) {
+        var itr = stats.iterator();
+        while (itr.hasNext()) {
+            if (! (itr.next() instanceof EmptyStatementTree)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+ 
+    var visitor = new EmptyCatchFinder() {
+        // current CompilationUnitTree
+        compUnit: null,
+        // current LineMap (pos -> line, column)
+        lineMap: null,
+        // current compilation unit's file name
+        fileName: null,
+
+        // overrides of TreeScanner methods
+
+        visitCompilationUnit: function(node, p) {
+            // capture info about current Compilation unit
+            this.compUnit = node;
+            this.lineMap = node.lineMap;
+            this.fileName = node.sourceFile.name;
+
+            // Using Java.super API to call super class method here
+            return Java.super(visitor).visitCompilationUnit(node, p);
+        },
+
+        visitCatch: function (node, p) {
+            var stats = node.block.statements;
+            if (stats.empty || hasOnlyEmptyStats(stats)) {
+                // print information on this empty catch
+                var pos = sourcePositions.getStartPosition(this.compUnit, node);
+                var line = this.lineMap.getLineNumber(pos);
+                var col = this.lineMap.getColumnNumber(pos);
+                print("Exception swallow" + " @ " + this.fileName + ":" + line + ":" + col);
+                // print(node);
+            }
+        }
+    }
+ 
+    for each (var cu in task.parse()) {
+        cu.accept(visitor, null);
+    }
+}
+ 
+// for each ".java" file in directory (recursively) and check it!
+function main(dir) {
+    Files.walk(dir.toPath()).
+      forEach(function(p) {
+        var name = p.toFile().absolutePath;
+        if (name.endsWith(".java")) {
+            try {
+                printEmptyCatch(p.toFile().getAbsolutePath());
+            } catch (e) {
+                print(e);
+            }
+        }
+      });
+}
+ 
+main(new File(arguments[0]));